| Message ID | 20210521124946.3617862-1-vkoul@kernel.org |
|---|---|
| Headers | show |
| Series | drm/msm: Add Display Stream Compression Support | expand |
On Fri, May 21, 2021 at 6:50 AM Vinod Koul <vkoul@kernel.org> wrote: > > Display Stream Compression (DSC) compresses the display stream in host which > is later decoded by panel. This series enables this for Qualcomm msm driver. > This was tested on Google Pixel3 phone which use LGE SW43408 panel. > > The changes include adding DT properties for DSC then hardware blocks support > required in DPU1 driver and support in encoder. We also add support in DSI > and introduce required topology changes. > > In order for panel to set the DSC parameters we add dsc in drm_panel and set > it from the msm driver. > > Complete changes which enable this for Pixel3 along with panel driver (not > part of this series) and DT changes can be found at: > git.linaro.org/people/vinod.koul/kernel.git pixel/dsc_rfc > > Comments welcome! This feels backwards to me. I've only skimmed this series, and the DT changes didn't come through for me, so perhaps I have an incomplete view. DSC is not MSM specific. There is a standard for it. Yet it looks like everything is implemented in a MSM specific way, and then pushed to the panel. So, every vendor needs to implement their vendor specific way to get the DSC info, and then push it to the panel? Seems wrong, given there is an actual standard for this feature. Additionally, we define panel properties (resolution, BPP, etc) at the panel, and have the display drivers pull it from the panel. However, for DSC, you do the reverse (define it in the display driver, and push it to the panel). If the argument is that DSC properties can be dynamic, well, so can resolution. Every panel for MSM MTPs supports multiple resolutions, yet we define that with the panel in Linux. Finally, I haven't seen the DT bits, but I'm concerned about using DT for this. It inherently excludes ACPI systems. You appear to have sdm845 support in this series, but what about ACPI boot on the Lenovo C630 for example? Or any of the 8cx laptops? We don't read the panel resolution, etc from DT, so why the DSC? I'm glad that work is being done to add DSC to Linux, it's something I struggled with when working on the 8998 mtp, and I realize this is a bit of a drive-by review. However, it seems like there should be a better way. > > Vinod Koul (13): > drm/dsc: Add dsc pps header init function > dt-bindings: msm/dsi: Document Display Stream Compression (DSC) > parameters > drm/msm/dsi: add support for dsc data > drm/msm/disp/dpu1: Add support for DSC > drm/msm/disp/dpu1: Add support for DSC in pingpong block > drm/msm/disp/dpu1: Add DSC support in RM > drm/msm/disp/dpu1: Add DSC for SDM845 to hw_catalog > drm/msm/disp/dpu1: Add DSC support in hw_ctl > drm/msm/disp/dpu1: Don't use DSC with mode_3d > drm/msm/disp/dpu1: Add support for DSC in encoder > drm/msm/disp/dpu1: Add support for DSC in topology > drm/msm/dsi: Add support for DSC configuration > drm/msm/dsi: Pass DSC params to drm_panel > > .../devicetree/bindings/display/msm/dsi.txt | 15 + > drivers/gpu/drm/drm_dsc.c | 11 + > drivers/gpu/drm/msm/Makefile | 1 + > drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 204 +++++++++++- > .../gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h | 11 + > .../drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c | 2 + > .../gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c | 22 ++ > .../gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h | 26 ++ > drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.c | 12 +- > drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.h | 2 + > drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c | 221 +++++++++++++ > drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.h | 79 +++++ > drivers/gpu/drm/msm/disp/dpu1/dpu_hw_mdss.h | 13 + > .../gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c | 32 ++ > .../gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.h | 14 + > drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h | 1 + > drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c | 32 ++ > drivers/gpu/drm/msm/disp/dpu1/dpu_rm.h | 1 + > drivers/gpu/drm/msm/dsi/dsi.xml.h | 10 + > drivers/gpu/drm/msm/dsi/dsi_host.c | 293 +++++++++++++++++- > drivers/gpu/drm/msm/msm_drv.h | 32 ++ > include/drm/drm_dsc.h | 16 + > include/drm/drm_panel.h | 7 + > 23 files changed, 1043 insertions(+), 14 deletions(-) > create mode 100644 drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c > create mode 100644 drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.h > > -- > 2.26.3 > > _______________________________________________ > Freedreno mailing list > Freedreno@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/freedreno
On Tue, May 25, 2021 at 11:46 PM Vinod Koul <vkoul@kernel.org> wrote: > > Hello Jeff, > > On 21-05-21, 08:09, Jeffrey Hugo wrote: > > On Fri, May 21, 2021 at 6:50 AM Vinod Koul <vkoul@kernel.org> wrote: > > > > > > Display Stream Compression (DSC) compresses the display stream in host which > > > is later decoded by panel. This series enables this for Qualcomm msm driver. > > > This was tested on Google Pixel3 phone which use LGE SW43408 panel. > > > > > > The changes include adding DT properties for DSC then hardware blocks support > > > required in DPU1 driver and support in encoder. We also add support in DSI > > > and introduce required topology changes. > > > > > > In order for panel to set the DSC parameters we add dsc in drm_panel and set > > > it from the msm driver. > > > > > > Complete changes which enable this for Pixel3 along with panel driver (not > > > part of this series) and DT changes can be found at: > > > git.linaro.org/people/vinod.koul/kernel.git pixel/dsc_rfc > > > > > > Comments welcome! > > > > This feels backwards to me. I've only skimmed this series, and the DT > > changes didn't come through for me, so perhaps I have an incomplete > > view. > > Not sure why, I see it on lore: > https://lore.kernel.org/dri-devel/20210521124946.3617862-3-vkoul@kernel.org/ > > > DSC is not MSM specific. There is a standard for it. Yet it looks > > like everything is implemented in a MSM specific way, and then pushed > > to the panel. So, every vendor needs to implement their vendor > > specific way to get the DSC info, and then push it to the panel? > > Seems wrong, given there is an actual standard for this feature. > > I have added slice and bpp info in the DT here under the host and then > pass the generic struct drm_dsc_config to panel which allows panel to > write the pps cmd > > Nothing above is MSM specific.. It can very well work with non MSM > controllers too. I disagree. The DT bindings you defined (thanks for the direct link) are MSM specific. I'm not talking (yet) about the properties you defined, but purely from the stand point that you defined the binding within the scope of the MSM dsi binding. No other vendor can use those bindings. Of course, if we look at the properties themselves, they are prefixed with "qcom", which is vendor specific. So, purely on the face of it, this is MSM specific. Assuming we want a DT solution for DSC, I think it should be something like Documentation/devicetree/bindings/clock/clock-bindings.txt (the first example that comes to mind), which is a non-vendor specific generic set of properties that each vendor/device specific binding can inherit. Panel has similar things. Specific to the properties, I don't much like that you duplicate BPP, which is already associated with the panel (although perhaps not in the scope of DT). What if the panel and your DSC bindings disagree? Also, I guess I need to ask, have you read the DSC spec? Last I looked, there were something like 3 dozen properties that could be configured. You have five in your proposed binding. To me, this is not a generic DSC solution, this is MSM specific (and frankly I don't think this supports all the configuration the MSM hardware can do, either). I'm surprised Rob Herring didn't have more to say on this. > I didn't envision DSC to be a specific thing, most of > the patches here are hardware enabling ones for DSC bits for MSM > hardware. > > > Additionally, we define panel properties (resolution, BPP, etc) at the > > panel, and have the display drivers pull it from the panel. However, > > for DSC, you do the reverse (define it in the display driver, and push > > it to the panel). If the argument is that DSC properties can be > > dynamic, well, so can resolution. Every panel for MSM MTPs supports > > multiple resolutions, yet we define that with the panel in Linux. > > I dont have an answer for that right now, to start with yes the > properties are in host but I am okay to discuss this and put wherever we > feel is most correct thing. I somehow dont like that we should pull > from panel DT and program host with that. Here using struct > drm_dsc_config allows me to configure panel based on resolution passed I somewhat agree that pulling from the panel and programing the host based on that is an odd solution, but we have it currently. Have a look at Documentation/devicetree/bindings/display/panel in particular panel-timing. All of that ends up informing the mdss programing anyways (particularly the dsi and its phy). So my problem is that we currently have a solution that seems to just need to be extended, and instead you have proposed a completely different solution which is arguably contradictory. However, I'd like to see thoughts from Rob Clark, David, and any others that typically handle this stuff (maybe Sam Ravenborg from the panel side?). I consider them to be the experts, and if they think your solution is the way to go, I'll shut up. I consider myself to be a novice that has dabbled in this area, and while this currently doesn't make sense to me, maybe I need some education here to see the light. > > Finally, I haven't seen the DT bits, but I'm concerned about using DT > > for this. It inherently excludes ACPI systems. You appear to have > > sdm845 support in this series, but what about ACPI boot on the Lenovo > > C630 for example? Or any of the 8cx laptops? We don't read the panel > > resolution, etc from DT, so why the DSC? > > But you must read from somewhere like ACPI tables. I think ACPI systems > would have some ACPI table info out there which would help on this. > Yes that is another task which we need to start with once we enable OF > systems. Frankly, I don't like the MSM ACPI solution that I've seen on the laptops. The ACPI assumes the entire MDSS (including DSI parts) and GPU is one device, and ultimately handled by one driver. That driver needs to get a value from UEFI (set by the bootloader) that is the "panel id". Then the driver calls into ACPI (I think its _ROM, but I might be mistaken, doing this from memory) with that id. It gets back a binary blob which is mostly an xml file (format is publicly documented) that contains the panel timings and such. Generally we've defined simple-panel entities for these, with the timings in code (you can see what Bjorn and I have upstreamed), and just match on the compatible. In summary, I don't mean to be difficult, I just think this solution needs more "baking".
On Wed, May 26, 2021 at 8:00 AM Jeffrey Hugo <jeffrey.l.hugo@gmail.com> wrote: > > On Tue, May 25, 2021 at 11:46 PM Vinod Koul <vkoul@kernel.org> wrote: > > > > Hello Jeff, > > > > On 21-05-21, 08:09, Jeffrey Hugo wrote: > > > On Fri, May 21, 2021 at 6:50 AM Vinod Koul <vkoul@kernel.org> wrote: > > > > > > > > Display Stream Compression (DSC) compresses the display stream in host which > > > > is later decoded by panel. This series enables this for Qualcomm msm driver. > > > > This was tested on Google Pixel3 phone which use LGE SW43408 panel. > > > > > > > > The changes include adding DT properties for DSC then hardware blocks support > > > > required in DPU1 driver and support in encoder. We also add support in DSI > > > > and introduce required topology changes. > > > > > > > > In order for panel to set the DSC parameters we add dsc in drm_panel and set > > > > it from the msm driver. > > > > > > > > Complete changes which enable this for Pixel3 along with panel driver (not > > > > part of this series) and DT changes can be found at: > > > > git.linaro.org/people/vinod.koul/kernel.git pixel/dsc_rfc > > > > > > > > Comments welcome! > > > > > > This feels backwards to me. I've only skimmed this series, and the DT > > > changes didn't come through for me, so perhaps I have an incomplete > > > view. > > > > Not sure why, I see it on lore: > > https://lore.kernel.org/dri-devel/20210521124946.3617862-3-vkoul@kernel.org/ > > > > > DSC is not MSM specific. There is a standard for it. Yet it looks > > > like everything is implemented in a MSM specific way, and then pushed > > > to the panel. So, every vendor needs to implement their vendor > > > specific way to get the DSC info, and then push it to the panel? > > > Seems wrong, given there is an actual standard for this feature. > > > > I have added slice and bpp info in the DT here under the host and then > > pass the generic struct drm_dsc_config to panel which allows panel to > > write the pps cmd > > > > Nothing above is MSM specific.. It can very well work with non MSM > > controllers too. > > I disagree. > > The DT bindings you defined (thanks for the direct link) are MSM > specific. I'm not talking (yet) about the properties you defined, but > purely from the stand point that you defined the binding within the > scope of the MSM dsi binding. No other vendor can use those bindings. > Of course, if we look at the properties themselves, they are prefixed > with "qcom", which is vendor specific. > > So, purely on the face of it, this is MSM specific. > > Assuming we want a DT solution for DSC, I think it should be something > like Documentation/devicetree/bindings/clock/clock-bindings.txt (the > first example that comes to mind), which is a non-vendor specific > generic set of properties that each vendor/device specific binding can > inherit. Panel has similar things. > > Specific to the properties, I don't much like that you duplicate BPP, > which is already associated with the panel (although perhaps not in > the scope of DT). What if the panel and your DSC bindings disagree? > Also, I guess I need to ask, have you read the DSC spec? Last I > looked, there were something like 3 dozen properties that could be > configured. You have five in your proposed binding. To me, this is > not a generic DSC solution, this is MSM specific (and frankly I don't > think this supports all the configuration the MSM hardware can do, > either). > > I'm surprised Rob Herring didn't have more to say on this. > > > I didn't envision DSC to be a specific thing, most of > > the patches here are hardware enabling ones for DSC bits for MSM > > hardware. > > > > > Additionally, we define panel properties (resolution, BPP, etc) at the > > > panel, and have the display drivers pull it from the panel. However, > > > for DSC, you do the reverse (define it in the display driver, and push > > > it to the panel). If the argument is that DSC properties can be > > > dynamic, well, so can resolution. Every panel for MSM MTPs supports > > > multiple resolutions, yet we define that with the panel in Linux. > > > > I dont have an answer for that right now, to start with yes the > > properties are in host but I am okay to discuss this and put wherever we > > feel is most correct thing. I somehow dont like that we should pull > > from panel DT and program host with that. Here using struct > > drm_dsc_config allows me to configure panel based on resolution passed > > I somewhat agree that pulling from the panel and programing the host > based on that is an odd solution, but we have it currently. Have a > look at Documentation/devicetree/bindings/display/panel in particular > panel-timing. All of that ends up informing the mdss programing > anyways (particularly the dsi and its phy). So my problem is that we > currently have a solution that seems to just need to be extended, and > instead you have proposed a completely different solution which is > arguably contradictory. > > However, I'd like to see thoughts from Rob Clark, David, and any > others that typically handle this stuff (maybe Sam Ravenborg from the > panel side?). I consider them to be the experts, and if they think > your solution is the way to go, I'll shut up. I consider myself to be > a novice that has dabbled in this area, and while this currently > doesn't make sense to me, maybe I need some education here to see the > light. > > > > Finally, I haven't seen the DT bits, but I'm concerned about using DT > > > for this. It inherently excludes ACPI systems. You appear to have > > > sdm845 support in this series, but what about ACPI boot on the Lenovo > > > C630 for example? Or any of the 8cx laptops? We don't read the panel > > > resolution, etc from DT, so why the DSC? > > > > But you must read from somewhere like ACPI tables. I think ACPI systems > > would have some ACPI table info out there which would help on this. > > Yes that is another task which we need to start with once we enable OF > > systems. > > Frankly, I don't like the MSM ACPI solution that I've seen on the laptops. > The ACPI assumes the entire MDSS (including DSI parts) and GPU is one > device, and ultimately handled by one driver. That driver needs to > get a value from UEFI (set by the bootloader) that is the "panel id". > Then the driver calls into ACPI (I think its _ROM, but I might be > mistaken, doing this from memory) with that id. It gets back a binary > blob which is mostly an xml file (format is publicly documented) that > contains the panel timings and such. tbh, I kinda suspect that having a single "gpu" device (which also includes venus, in addition to display, IIRC) in the ACPI tables is a windowsism, trying to make things look to userspace like a single "GPU card" in the x86 world.. but either way, I think the ACPI tables on the windows arm laptops which use dsi->bridge->edp is too much of a lost cause to even consider here. Possibly ACPI boot on these devices would be more feasible on newer devices which have direct eDP out of the SoC without requiring external bridge/panel glue. I'd worry more about what makes sense in a DT world, when it comes to DT bindings. BR, -R > Generally we've defined simple-panel entities for these, with the > timings in code (you can see what Bjorn and I have upstreamed), and > just match on the compatible. > > In summary, I don't mean to be difficult, I just think this solution > needs more "baking".
On 26-05-21, 09:00, Jeffrey Hugo wrote: > On Tue, May 25, 2021 at 11:46 PM Vinod Koul <vkoul@kernel.org> wrote: > > On 21-05-21, 08:09, Jeffrey Hugo wrote: > > > On Fri, May 21, 2021 at 6:50 AM Vinod Koul <vkoul@kernel.org> wrote: > > > > > > > > Display Stream Compression (DSC) compresses the display stream in host which > > > > is later decoded by panel. This series enables this for Qualcomm msm driver. > > > > This was tested on Google Pixel3 phone which use LGE SW43408 panel. > > > > > > > > The changes include adding DT properties for DSC then hardware blocks support > > > > required in DPU1 driver and support in encoder. We also add support in DSI > > > > and introduce required topology changes. > > > > > > > > In order for panel to set the DSC parameters we add dsc in drm_panel and set > > > > it from the msm driver. > > > > > > > > Complete changes which enable this for Pixel3 along with panel driver (not > > > > part of this series) and DT changes can be found at: > > > > git.linaro.org/people/vinod.koul/kernel.git pixel/dsc_rfc > > > > > > > > Comments welcome! > > > > > > This feels backwards to me. I've only skimmed this series, and the DT > > > changes didn't come through for me, so perhaps I have an incomplete > > > view. > > > > Not sure why, I see it on lore: > > https://lore.kernel.org/dri-devel/20210521124946.3617862-3-vkoul@kernel.org/ > > > > > DSC is not MSM specific. There is a standard for it. Yet it looks > > > like everything is implemented in a MSM specific way, and then pushed > > > to the panel. So, every vendor needs to implement their vendor > > > specific way to get the DSC info, and then push it to the panel? > > > Seems wrong, given there is an actual standard for this feature. > > > > I have added slice and bpp info in the DT here under the host and then > > pass the generic struct drm_dsc_config to panel which allows panel to > > write the pps cmd > > > > Nothing above is MSM specific.. It can very well work with non MSM > > controllers too. > > I disagree. > > The DT bindings you defined (thanks for the direct link) are MSM > specific. I'm not talking (yet) about the properties you defined, but > purely from the stand point that you defined the binding within the > scope of the MSM dsi binding. No other vendor can use those bindings. > Of course, if we look at the properties themselves, they are prefixed > with "qcom", which is vendor specific. > > So, purely on the face of it, this is MSM specific. > > Assuming we want a DT solution for DSC, I think it should be something > like Documentation/devicetree/bindings/clock/clock-bindings.txt (the > first example that comes to mind), which is a non-vendor specific > generic set of properties that each vendor/device specific binding can > inherit. Panel has similar things. > > Specific to the properties, I don't much like that you duplicate BPP, > which is already associated with the panel (although perhaps not in > the scope of DT). What if the panel and your DSC bindings disagree? > Also, I guess I need to ask, have you read the DSC spec? Last I > looked, there were something like 3 dozen properties that could be > configured. You have five in your proposed binding. To me, this is > not a generic DSC solution, this is MSM specific (and frankly I don't > think this supports all the configuration the MSM hardware can do, > either). I would concede the point that DT is msm specific. I dont disagree on making them a common dsc biding which anyone can use. I think your idea does have merits... I am still not sure who should include these properties, would it be the panel or host. Either would work and rest of the system can use these properties...
On 27-05-21, 16:30, Rob Clark wrote: > On Wed, May 26, 2021 at 8:00 AM Jeffrey Hugo <jeffrey.l.hugo@gmail.com> wrote: > > On Tue, May 25, 2021 at 11:46 PM Vinod Koul <vkoul@kernel.org> wrote: > > Frankly, I don't like the MSM ACPI solution that I've seen on the laptops. > > The ACPI assumes the entire MDSS (including DSI parts) and GPU is one > > device, and ultimately handled by one driver. That driver needs to > > get a value from UEFI (set by the bootloader) that is the "panel id". > > Then the driver calls into ACPI (I think its _ROM, but I might be > > mistaken, doing this from memory) with that id. It gets back a binary > > blob which is mostly an xml file (format is publicly documented) that > > contains the panel timings and such. > > tbh, I kinda suspect that having a single "gpu" device (which also > includes venus, in addition to display, IIRC) in the ACPI tables is a > windowsism, trying to make things look to userspace like a single "GPU > card" in the x86 world.. but either way, I think the ACPI tables on > the windows arm laptops which use dsi->bridge->edp is too much of a > lost cause to even consider here. Possibly ACPI boot on these devices > would be more feasible on newer devices which have direct eDP out of > the SoC without requiring external bridge/panel glue. yeah that is always a very different world. although it might make sense to use information in tables and try to deduce information about the system can be helpful... > I'd worry more about what makes sense in a DT world, when it comes to > DT bindings. And do you have thoughts on that..?
On 2021-06-02 04:01, Vinod Koul wrote: > On 27-05-21, 16:30, Rob Clark wrote: >> On Wed, May 26, 2021 at 8:00 AM Jeffrey Hugo >> <jeffrey.l.hugo@gmail.com> wrote: >> > On Tue, May 25, 2021 at 11:46 PM Vinod Koul <vkoul@kernel.org> wrote: > >> > Frankly, I don't like the MSM ACPI solution that I've seen on the laptops. >> > The ACPI assumes the entire MDSS (including DSI parts) and GPU is one >> > device, and ultimately handled by one driver. That driver needs to >> > get a value from UEFI (set by the bootloader) that is the "panel id". >> > Then the driver calls into ACPI (I think its _ROM, but I might be >> > mistaken, doing this from memory) with that id. It gets back a binary >> > blob which is mostly an xml file (format is publicly documented) that >> > contains the panel timings and such. >> >> tbh, I kinda suspect that having a single "gpu" device (which also >> includes venus, in addition to display, IIRC) in the ACPI tables is a >> windowsism, trying to make things look to userspace like a single "GPU >> card" in the x86 world.. but either way, I think the ACPI tables on >> the windows arm laptops which use dsi->bridge->edp is too much of a >> lost cause to even consider here. Possibly ACPI boot on these devices >> would be more feasible on newer devices which have direct eDP out of >> the SoC without requiring external bridge/panel glue. > > yeah that is always a very different world. although it might make > sense > to use information in tables and try to deduce information about the > system can be helpful... > >> I'd worry more about what makes sense in a DT world, when it comes to >> DT bindings. > > And do you have thoughts on that..? At the moment, I will comment on the bindings first and my idea on how to proceed. The bindings mentioned here: https://lore.kernel.org/dri-devel/20210521124946.3617862-3-vkoul@kernel.org/ seem to be just taken directly from downstream which was not the plan. I think all of these should be part of the generic panel bindings as none of these are QC specific: @@ -188,6 +195,14 @@ Example: qcom,master-dsi; qcom,sync-dual-dsi; + qcom,mdss-dsc-enabled; + qcom,mdss-slice-height = <16>; + qcom,mdss-slice-width = <540>; + qcom,mdss-slice-per-pkt = <1>; + qcom,mdss-bit-per-component = <8>; + qcom,mdss-bit-per-pixel = <8>; + qcom,mdss-block-prediction-enable; + How about having a panel-dsc.yaml which will have these properties and have a panel-dsc node to have this information? I would like to hear the feedback on this proposal then the series can be reworked. Thanks Abhinav
On Wed, Jun 2, 2021 at 4:01 AM Vinod Koul <vkoul@kernel.org> wrote: > > On 27-05-21, 16:30, Rob Clark wrote: > > On Wed, May 26, 2021 at 8:00 AM Jeffrey Hugo <jeffrey.l.hugo@gmail.com> wrote: > > > On Tue, May 25, 2021 at 11:46 PM Vinod Koul <vkoul@kernel.org> wrote: > > > > Frankly, I don't like the MSM ACPI solution that I've seen on the laptops. > > > The ACPI assumes the entire MDSS (including DSI parts) and GPU is one > > > device, and ultimately handled by one driver. That driver needs to > > > get a value from UEFI (set by the bootloader) that is the "panel id". > > > Then the driver calls into ACPI (I think its _ROM, but I might be > > > mistaken, doing this from memory) with that id. It gets back a binary > > > blob which is mostly an xml file (format is publicly documented) that > > > contains the panel timings and such. > > > > tbh, I kinda suspect that having a single "gpu" device (which also > > includes venus, in addition to display, IIRC) in the ACPI tables is a > > windowsism, trying to make things look to userspace like a single "GPU > > card" in the x86 world.. but either way, I think the ACPI tables on > > the windows arm laptops which use dsi->bridge->edp is too much of a > > lost cause to even consider here. Possibly ACPI boot on these devices > > would be more feasible on newer devices which have direct eDP out of > > the SoC without requiring external bridge/panel glue. > > yeah that is always a very different world. although it might make sense > to use information in tables and try to deduce information about the > system can be helpful... > > > I'd worry more about what makes sense in a DT world, when it comes to > > DT bindings. > > And do you have thoughts on that..? Only that I wouldn't get too hung up on existing snapdragon ACPI tables.. not sure if there is prior art as far as ACPI tables for this on x86 systems, if so that *might* be a thing to consider, but otherwise it does sound a bit like we want less qcom specific bindings here. But other than that I'll leave it to folks who spend more time thinking about bindings.. left to my own devices I'd come up with a point solution and go back to working on mesa, so that probably isn't the opinion you want to follow ;-) BR, -R
On 03-06-21, 16:40, abhinavk@codeaurora.org wrote: > On 2021-06-02 04:01, Vinod Koul wrote: > > On 27-05-21, 16:30, Rob Clark wrote: > > > > yeah that is always a very different world. although it might make sense > > to use information in tables and try to deduce information about the > > system can be helpful... > > > > > I'd worry more about what makes sense in a DT world, when it comes to > > > DT bindings. > > > > And do you have thoughts on that..? > > At the moment, I will comment on the bindings first and my idea on how to > proceed. > The bindings mentioned here: > https://lore.kernel.org/dri-devel/20210521124946.3617862-3-vkoul@kernel.org/ > seem to be just > taken directly from downstream which was not the plan. > > I think all of these should be part of the generic panel bindings as none of > these are QC specific: Okay so we have discussed this w/ Bjorn and Abhinav and here are the conclusions and recommendations for binding 1. the properties are generic and not msm specific 2. The host supports multiple formats but the one we choose depends mostly upon panel. Notably host runs the config which the panel supports. So the recommendations is to add a table of dsc properties in the panel driver. No DT binding here. I should also note that for DP we should be able to calculate these values from EDID like the i915 driver seems to do With this I will drop the binding patch and move dsc properties to panel driver Thanks -- ~Vinod
Display Stream Compression (DSC) compresses the display stream in host which is later decoded by panel. This series enables this for Qualcomm msm driver. This was tested on Google Pixel3 phone which use LGE SW43408 panel. The changes include adding DT properties for DSC then hardware blocks support required in DPU1 driver and support in encoder. We also add support in DSI and introduce required topology changes. In order for panel to set the DSC parameters we add dsc in drm_panel and set it from the msm driver. Complete changes which enable this for Pixel3 along with panel driver (not part of this series) and DT changes can be found at: git.linaro.org/people/vinod.koul/kernel.git pixel/dsc_rfc Comments welcome! Vinod Koul (13): drm/dsc: Add dsc pps header init function dt-bindings: msm/dsi: Document Display Stream Compression (DSC) parameters drm/msm/dsi: add support for dsc data drm/msm/disp/dpu1: Add support for DSC drm/msm/disp/dpu1: Add support for DSC in pingpong block drm/msm/disp/dpu1: Add DSC support in RM drm/msm/disp/dpu1: Add DSC for SDM845 to hw_catalog drm/msm/disp/dpu1: Add DSC support in hw_ctl drm/msm/disp/dpu1: Don't use DSC with mode_3d drm/msm/disp/dpu1: Add support for DSC in encoder drm/msm/disp/dpu1: Add support for DSC in topology drm/msm/dsi: Add support for DSC configuration drm/msm/dsi: Pass DSC params to drm_panel .../devicetree/bindings/display/msm/dsi.txt | 15 + drivers/gpu/drm/drm_dsc.c | 11 + drivers/gpu/drm/msm/Makefile | 1 + drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 204 +++++++++++- .../gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h | 11 + .../drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c | 2 + .../gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c | 22 ++ .../gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h | 26 ++ drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.c | 12 +- drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.h | 2 + drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c | 221 +++++++++++++ drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.h | 79 +++++ drivers/gpu/drm/msm/disp/dpu1/dpu_hw_mdss.h | 13 + .../gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c | 32 ++ .../gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.h | 14 + drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h | 1 + drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c | 32 ++ drivers/gpu/drm/msm/disp/dpu1/dpu_rm.h | 1 + drivers/gpu/drm/msm/dsi/dsi.xml.h | 10 + drivers/gpu/drm/msm/dsi/dsi_host.c | 293 +++++++++++++++++- drivers/gpu/drm/msm/msm_drv.h | 32 ++ include/drm/drm_dsc.h | 16 + include/drm/drm_panel.h | 7 + 23 files changed, 1043 insertions(+), 14 deletions(-) create mode 100644 drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c create mode 100644 drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.h