mbox series

[v3,00/16] eDP: Support probing eDP panels dynamically instead of hardcoding

Message ID 20210901201934.1084250-1-dianders@chromium.org
Headers show
Series eDP: Support probing eDP panels dynamically instead of hardcoding | expand

Message

Doug Anderson Sept. 1, 2021, 8:19 p.m. UTC
The goal of this patch series is to move away from hardcoding exact
eDP panels in device tree files. As discussed in the various patches
in this series (I'm not repeating everything here), most eDP panels
are 99% probable and we can get that last 1% by allowing two "power
up" delays to be specified in the device tree file and then using the
panel ID (found in the EDID) to look up additional power sequencing
delays for the panel.

This patch series is the logical contiunation of a previous patch
series where I proposed solving this problem by adding a
board-specific compatible string [1]. In the discussion that followed
it sounded like people were open to something like the solution
proposed in this new series.

In version 2 I got rid of the idea that we could have a "fallback"
compatible string that we'd use if we didn't recognize the ID in the
EDID. This simplifies the bindings a lot and the implementation
somewhat. As a result of not having a "fallback", though, I'm not
confident in transitioning any existing boards over to this since
we'll have to fallback to very conservative timings if we don't
recognize the ID from the EDID and I can't guarantee that I've seen
every panel that might have shipped on an existing product. The plan
is to use "edp-panel" only on new boards or new revisions of old
boards where we can guarantee that every EDID that ships out of the
factory has an ID in the table.

Version 3 of this series now splits out all eDP panels to their own
driver and adds the generic eDP panel support to this new driver. I
believe this is what Sam was looking for [2].

[1] https://lore.kernel.org/r/YFKQaXOmOwYyeqvM@google.com/
[2] https://lore.kernel.org/r/YRTsFNTn%2FT8fLxyB@ravnborg.org/

Changes in v3:
- Decode hex product ID w/ same endianness as everyone else.
- ("Reorder logicpd_type_28...") patch new for v3.
- Split eDP panels patch new for v3.
- Move wayward panels patch new for v3.
- ("Non-eDP panels don't need "HPD" handling") new for v3.
- Split the delay structure out patch just on eDP now.
- ("Better describe eDP panel delays") new for v3.
- Fix "prepare_to_enable" patch new for v3.
- ("Don't re-read the EDID every time") moved to eDP only patch.
- Generic "edp-panel" handled by the eDP panel driver now.
- Change init order to we power at the end.
- Adjust endianness of product ID.
- Fallback to conservative delays if panel not recognized.
- Add Sharp LQ116M1JW10 to table.
- Add AUO B116XAN06.1 to table.
- Rename delays more generically so they can be reused.

Changes in v2:
- No longer allow fallback to panel-simple.
- Add "-ms" suffix to delays.
- Don't support a "fallback" panel. Probed panels must be probed.
- Not based on patch to copy "desc"--just allocate for probed panels.
- Add "-ms" suffix to delays.

Douglas Anderson (16):
  dt-bindings: drm/panel-simple-edp: Introduce generic eDP panels
  drm/edid: Break out reading block 0 of the EDID
  drm/edid: Allow the querying/working with the panel ID from the EDID
  drm/panel-simple: Reorder logicpd_type_28 / mitsubishi_aa070mc01
  drm/panel-simple-edp: Split eDP panels out of panel-simple
  ARM: configs: Everyone who had PANEL_SIMPLE now gets PANEL_SIMPLE_EDP
  arm64: defconfig: Everyone who had PANEL_SIMPLE now gets
    PANEL_SIMPLE_EDP
  MIPS: configs: Everyone who had PANEL_SIMPLE now gets PANEL_SIMPLE_EDP
  drm/panel-simple-edp: Move some wayward panels to the eDP driver
  drm/panel-simple: Non-eDP panels don't need "HPD" handling
  drm/panel-simple-edp: Split the delay structure out
  drm/panel-simple-edp: Better describe eDP panel delays
  drm/panel-simple-edp: hpd_reliable shouldn't be subtraced from
    hpd_absent
  drm/panel-simple-edp: Fix "prepare_to_enable" if panel doesn't handle
    HPD
  drm/panel-simple-edp: Don't re-read the EDID every time we power off
    the panel
  drm/panel-simple-edp: Implement generic "edp-panel"s probed by EDID

 .../bindings/display/panel/panel-edp.yaml     |  188 ++
 arch/arm/configs/at91_dt_defconfig            |    1 +
 arch/arm/configs/exynos_defconfig             |    1 +
 arch/arm/configs/imx_v6_v7_defconfig          |    1 +
 arch/arm/configs/lpc32xx_defconfig            |    1 +
 arch/arm/configs/multi_v5_defconfig           |    1 +
 arch/arm/configs/multi_v7_defconfig           |    1 +
 arch/arm/configs/omap2plus_defconfig          |    1 +
 arch/arm/configs/qcom_defconfig               |    1 +
 arch/arm/configs/realview_defconfig           |    1 +
 arch/arm/configs/sama5_defconfig              |    1 +
 arch/arm/configs/shmobile_defconfig           |    1 +
 arch/arm/configs/sunxi_defconfig              |    1 +
 arch/arm/configs/tegra_defconfig              |    1 +
 arch/arm/configs/versatile_defconfig          |    1 +
 arch/arm/configs/vexpress_defconfig           |    1 +
 arch/arm64/configs/defconfig                  |    1 +
 arch/mips/configs/qi_lb60_defconfig           |    1 +
 arch/mips/configs/rs90_defconfig              |    1 +
 drivers/gpu/drm/drm_edid.c                    |  121 +-
 drivers/gpu/drm/panel/Kconfig                 |   16 +-
 drivers/gpu/drm/panel/Makefile                |    1 +
 drivers/gpu/drm/panel/panel-simple-edp.c      | 1895 +++++++++++++++++
 drivers/gpu/drm/panel/panel-simple.c          | 1100 +---------
 include/drm/drm_edid.h                        |   47 +
 25 files changed, 2293 insertions(+), 1093 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/display/panel/panel-edp.yaml
 create mode 100644 drivers/gpu/drm/panel/panel-simple-edp.c

Comments

Doug Anderson Sept. 9, 2021, 12:24 a.m. UTC | #1
Hi,

On Sun, Sep 5, 2021 at 11:55 AM Sam Ravnborg <sam@ravnborg.org> wrote:
>
> Hi Douglas,
>
> On Wed, Sep 01, 2021 at 01:19:18PM -0700, Douglas Anderson wrote:
> > The goal of this patch series is to move away from hardcoding exact
> > eDP panels in device tree files. As discussed in the various patches
> > in this series (I'm not repeating everything here), most eDP panels
> > are 99% probable and we can get that last 1% by allowing two "power
> > up" delays to be specified in the device tree file and then using the
> > panel ID (found in the EDID) to look up additional power sequencing
> > delays for the panel.
> >
> > This patch series is the logical contiunation of a previous patch
> > series where I proposed solving this problem by adding a
> > board-specific compatible string [1]. In the discussion that followed
> > it sounded like people were open to something like the solution
> > proposed in this new series.
> >
> > In version 2 I got rid of the idea that we could have a "fallback"
> > compatible string that we'd use if we didn't recognize the ID in the
> > EDID. This simplifies the bindings a lot and the implementation
> > somewhat. As a result of not having a "fallback", though, I'm not
> > confident in transitioning any existing boards over to this since
> > we'll have to fallback to very conservative timings if we don't
> > recognize the ID from the EDID and I can't guarantee that I've seen
> > every panel that might have shipped on an existing product. The plan
> > is to use "edp-panel" only on new boards or new revisions of old
> > boards where we can guarantee that every EDID that ships out of the
> > factory has an ID in the table.
> >
> > Version 3 of this series now splits out all eDP panels to their own
> > driver and adds the generic eDP panel support to this new driver. I
> > believe this is what Sam was looking for [2].
> >
> > [1] https://lore.kernel.org/r/YFKQaXOmOwYyeqvM@google.com/
> > [2] https://lore.kernel.org/r/YRTsFNTn%2FT8fLxyB@ravnborg.org/
> >
> > Changes in v3:
> > - Decode hex product ID w/ same endianness as everyone else.
> > - ("Reorder logicpd_type_28...") patch new for v3.
> > - Split eDP panels patch new for v3.
> > - Move wayward panels patch new for v3.
> > - ("Non-eDP panels don't need "HPD" handling") new for v3.
> > - Split the delay structure out patch just on eDP now.
> > - ("Better describe eDP panel delays") new for v3.
> > - Fix "prepare_to_enable" patch new for v3.
> > - ("Don't re-read the EDID every time") moved to eDP only patch.
> > - Generic "edp-panel" handled by the eDP panel driver now.
> > - Change init order to we power at the end.
> > - Adjust endianness of product ID.
> > - Fallback to conservative delays if panel not recognized.
> > - Add Sharp LQ116M1JW10 to table.
> > - Add AUO B116XAN06.1 to table.
> > - Rename delays more generically so they can be reused.
> >
> > Changes in v2:
> > - No longer allow fallback to panel-simple.
> > - Add "-ms" suffix to delays.
> > - Don't support a "fallback" panel. Probed panels must be probed.
> > - Not based on patch to copy "desc"--just allocate for probed panels.
> > - Add "-ms" suffix to delays.
> >
> > Douglas Anderson (16):
> >   dt-bindings: drm/panel-simple-edp: Introduce generic eDP panels
> >   drm/edid: Break out reading block 0 of the EDID
> >   drm/edid: Allow the querying/working with the panel ID from the EDID
> >   drm/panel-simple: Reorder logicpd_type_28 / mitsubishi_aa070mc01
> >   drm/panel-simple-edp: Split eDP panels out of panel-simple
> >   ARM: configs: Everyone who had PANEL_SIMPLE now gets PANEL_SIMPLE_EDP
> >   arm64: defconfig: Everyone who had PANEL_SIMPLE now gets
> >     PANEL_SIMPLE_EDP
> >   MIPS: configs: Everyone who had PANEL_SIMPLE now gets PANEL_SIMPLE_EDP
> >   drm/panel-simple-edp: Move some wayward panels to the eDP driver
> >   drm/panel-simple: Non-eDP panels don't need "HPD" handling
> >   drm/panel-simple-edp: Split the delay structure out
> >   drm/panel-simple-edp: Better describe eDP panel delays
> >   drm/panel-simple-edp: hpd_reliable shouldn't be subtraced from
> >     hpd_absent
> >   drm/panel-simple-edp: Fix "prepare_to_enable" if panel doesn't handle
> >     HPD
> >   drm/panel-simple-edp: Don't re-read the EDID every time we power off
> >     the panel
> >   drm/panel-simple-edp: Implement generic "edp-panel"s probed by EDID
>
> Thanks for looking into this. I really like the outcome.
> We have panel-simple that now (mostly) handle simple panels,
> and thus all the eDP functionality is in a separate driver.
>
> I have provided a few nits.
> My only take on this is the naming - as we do not want to confuse
> panel-simple and panel-edp I strongly suggest renaming the driver to
> panel-edp.

Sure, I'll do that. I was trying to express the fact that the new
"panel-edp" driver won't actually handle _all_ eDP panels, only the
eDP panels that are (comparatively) simpler. For instance, I'm not
planning to handle panel-samsung-atna33xc20.c in "panel-edp". I guess
people will figure it out, though.


> And then rename the corresponding Kconfig entry.
>
> With these few changes all patches are:
> Acked-by: Sam Ravnborg <sam@ravnborg.org>

Thanks, I'll add it to the patches. If there's anything major I need
to change I'll give you a yell to make sure you see it.


> For bisectability I suggest to move the defconfig patches up before you
> introduce the new Kconfig symbol. Or maybe they will be added via
> another tree and then this is not possible to control

Yup, I'll do that. There was some question about the defconfig patch
but they are hopefully cleared up now.


> I assume you will apply the patches yourself.

Sure, I can do that with your Ack. I'll also make sure that patches
that Jani commented on get resolved.


-Doug