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[0/2] drm/msm/dpu: two fixes targeting 6.11

Message ID 20240709-dpu-fix-wb-v1-0-448348bfd4cb@linaro.org
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Series drm/msm/dpu: two fixes targeting 6.11 | expand

Message

Dmitry Baryshkov July 9, 2024, 1:48 p.m. UTC
Leonard Lausen reported an issue with suspend/resume of the sc7180
devices. Fix the WB atomic check, which caused the issue. Also make sure
that DPU debugging logs are always directed to the drm_debug / DRIVER so
that usual drm.debug masks work in an expected way.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
Dmitry Baryshkov (2):
      drm/msm/dpu1: don't choke on disabling the writeback connector
      drm/msm/dpu: don't play tricks with debug macros

 drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h       | 14 ++------------
 drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.c | 14 +++++++-------
 2 files changed, 9 insertions(+), 19 deletions(-)
---
base-commit: 0b58e108042b0ed28a71cd7edf5175999955b233
change-id: 20240709-dpu-fix-wb-6cd57e3eb182

Best regards,

Comments

Dmitry Baryshkov July 10, 2024, 7:40 a.m. UTC | #1
On Tue, 9 Jul 2024 at 22:39, Abhinav Kumar <quic_abhinavk@quicinc.com> wrote:
>
>
>
> On 7/9/2024 6:48 AM, Dmitry Baryshkov wrote:
> > DPU debugging macros need to be converted to a proper drm_debug_*
> > macros, however this is a going an intrusive patch, not suitable for a
> > fix. Wire DPU_DEBUG and DPU_DEBUG_DRIVER to always use DRM_DEBUG_DRIVER
> > to make sure that DPU debugging messages always end up in the drm debug
> > messages and are controlled via the usual drm.debug mask.
> >
>
> These macros have been deprecated, is this waht you meant by the
> conversion to proper drm_debug_*?

Yes. Drop the driver-specific wrappers where they don't make sense.
Use sensible format strings in the cases where it actually does (like
VIDENC or _PLANE)

>
> /* NOTE: this is deprecated in favor of drm_dbg(NULL, ...). */
> #define DRM_DEBUG_DRIVER(fmt, ...)                                      \
>          __drm_dbg(DRM_UT_DRIVER, fmt, ##__VA_ARGS__)
>
> I think all that this macro was doing was to have appropriate DRM_UT_*
> macros enabled before calling the corresponding DRM_DEBUG_* macros. But
> I think what was incorrect here is for DPU_DEBUG, we could have used
> DRM_UT_CORE instead of DRM_UT_KMS.

It pretty much tries to overplay the existing drm debugging mechanism
by either sending the messages to the DRM channel or just using
pr_debug. With DYNAMIC_DEBUG being disabled pr_debug is just an empty
macro, so all the messages can end up in /dev/null. We should not be
trying to be too smart, using standard DRM_DEBUG_DRIVER should be
enough. This way all driver-related messages are controlled by
drm.debug including or excluding the 0x02 bit.


>
> And DRM_DEBUG_DRIVER should have been used instead of DRM_ERROR.
>
> Was this causing the issue of the prints not getting enabled?

I pretty much think so.

>
> > Fixes: 25fdd5933e4c ("drm/msm: Add SDM845 DPU support")
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> > ---
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h | 14 ++------------
> >   1 file changed, 2 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
> > index e2adc937ea63..935ff6fd172c 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
> > @@ -31,24 +31,14 @@
> >    * @fmt: Pointer to format string
> >    */
> >   #define DPU_DEBUG(fmt, ...)                                                \
> > -     do {                                                               \
> > -             if (drm_debug_enabled(DRM_UT_KMS))                         \
> > -                     DRM_DEBUG(fmt, ##__VA_ARGS__); \
> > -             else                                                       \
> > -                     pr_debug(fmt, ##__VA_ARGS__);                      \
> > -     } while (0)
> > +     DRM_DEBUG_DRIVER(fmt, ##__VA_ARGS__)
> >
> >   /**
> >    * DPU_DEBUG_DRIVER - macro for hardware driver logging
> >    * @fmt: Pointer to format string
> >    */
> >   #define DPU_DEBUG_DRIVER(fmt, ...)                                         \
> > -     do {                                                               \
> > -             if (drm_debug_enabled(DRM_UT_DRIVER))                      \
> > -                     DRM_ERROR(fmt, ##__VA_ARGS__); \
> > -             else                                                       \
> > -                     pr_debug(fmt, ##__VA_ARGS__);                      \
> > -     } while (0)
> > +     DRM_DEBUG_DRIVER(fmt, ##__VA_ARGS__)
> >
> >   #define DPU_ERROR(fmt, ...) pr_err("[dpu error]" fmt, ##__VA_ARGS__)
> >   #define DPU_ERROR_RATELIMITED(fmt, ...) pr_err_ratelimited("[dpu error]" fmt, ##__VA_ARGS__)
> >
Abhinav Kumar July 11, 2024, 6:03 p.m. UTC | #2
On 7/10/2024 12:40 AM, Dmitry Baryshkov wrote:
> On Tue, 9 Jul 2024 at 22:39, Abhinav Kumar <quic_abhinavk@quicinc.com> wrote:
>>
>>
>>
>> On 7/9/2024 6:48 AM, Dmitry Baryshkov wrote:
>>> DPU debugging macros need to be converted to a proper drm_debug_*
>>> macros, however this is a going an intrusive patch, not suitable for a
>>> fix. Wire DPU_DEBUG and DPU_DEBUG_DRIVER to always use DRM_DEBUG_DRIVER
>>> to make sure that DPU debugging messages always end up in the drm debug
>>> messages and are controlled via the usual drm.debug mask.
>>>
>>
>> These macros have been deprecated, is this waht you meant by the
>> conversion to proper drm_debug_*?
> 
> Yes. Drop the driver-specific wrappers where they don't make sense.
> Use sensible format strings in the cases where it actually does (like
> VIDENC or _PLANE)
> 

Ack but we need to not just drop the wrappers but drop the usage of 
these macros as well because it is documented that they are deprecated.

So I assume you want to get this in and do that as a follow up change?

>>
>> /* NOTE: this is deprecated in favor of drm_dbg(NULL, ...). */
>> #define DRM_DEBUG_DRIVER(fmt, ...)                                      \
>>           __drm_dbg(DRM_UT_DRIVER, fmt, ##__VA_ARGS__)
>>
>> I think all that this macro was doing was to have appropriate DRM_UT_*
>> macros enabled before calling the corresponding DRM_DEBUG_* macros. But
>> I think what was incorrect here is for DPU_DEBUG, we could have used
>> DRM_UT_CORE instead of DRM_UT_KMS.
> 
> It pretty much tries to overplay the existing drm debugging mechanism
> by either sending the messages to the DRM channel or just using
> pr_debug. With DYNAMIC_DEBUG being disabled pr_debug is just an empty
> macro, so all the messages can end up in /dev/null. We should not be
> trying to be too smart, using standard DRM_DEBUG_DRIVER should be
> enough. This way all driver-related messages are controlled by
> drm.debug including or excluding the 0x02 bit.
> 
> 
>>
>> And DRM_DEBUG_DRIVER should have been used instead of DRM_ERROR.
>>
>> Was this causing the issue of the prints not getting enabled?
> 
> I pretty much think so.
> 

Alright, I am okay with the approach, just one minor suggestion, to keep 
the behavior intact, previously the code wanted DPU_DEBUG to be 
controlled by DRM_UT_KMS and DPU_DEBUG_DRIVER controlled by DRM_UT_DRIVER.

Keeping that intact, we need to use DRM_DEBUG_KMS for DPU_DEBUG?

>>
>>> Fixes: 25fdd5933e4c ("drm/msm: Add SDM845 DPU support")
>>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>>> ---
>>>    drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h | 14 ++------------
>>>    1 file changed, 2 insertions(+), 12 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
>>> index e2adc937ea63..935ff6fd172c 100644
>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
>>> @@ -31,24 +31,14 @@
>>>     * @fmt: Pointer to format string
>>>     */
>>>    #define DPU_DEBUG(fmt, ...)                                                \
>>> -     do {                                                               \
>>> -             if (drm_debug_enabled(DRM_UT_KMS))                         \
>>> -                     DRM_DEBUG(fmt, ##__VA_ARGS__); \
>>> -             else                                                       \
>>> -                     pr_debug(fmt, ##__VA_ARGS__);                      \
>>> -     } while (0)
>>> +     DRM_DEBUG_DRIVER(fmt, ##__VA_ARGS__)
>>>
>>>    /**
>>>     * DPU_DEBUG_DRIVER - macro for hardware driver logging
>>>     * @fmt: Pointer to format string
>>>     */
>>>    #define DPU_DEBUG_DRIVER(fmt, ...)                                         \
>>> -     do {                                                               \
>>> -             if (drm_debug_enabled(DRM_UT_DRIVER))                      \
>>> -                     DRM_ERROR(fmt, ##__VA_ARGS__); \
>>> -             else                                                       \
>>> -                     pr_debug(fmt, ##__VA_ARGS__);                      \
>>> -     } while (0)
>>> +     DRM_DEBUG_DRIVER(fmt, ##__VA_ARGS__)
>>>
>>>    #define DPU_ERROR(fmt, ...) pr_err("[dpu error]" fmt, ##__VA_ARGS__)
>>>    #define DPU_ERROR_RATELIMITED(fmt, ...) pr_err_ratelimited("[dpu error]" fmt, ##__VA_ARGS__)
>>>
> 
> 
>
Dmitry Baryshkov July 13, 2024, 3:38 p.m. UTC | #3
On Thu, Jul 11, 2024 at 11:03:15AM GMT, Abhinav Kumar wrote:
> 
> 
> On 7/10/2024 12:40 AM, Dmitry Baryshkov wrote:
> > On Tue, 9 Jul 2024 at 22:39, Abhinav Kumar <quic_abhinavk@quicinc.com> wrote:
> > > 
> > > 
> > > 
> > > On 7/9/2024 6:48 AM, Dmitry Baryshkov wrote:
> > > > DPU debugging macros need to be converted to a proper drm_debug_*
> > > > macros, however this is a going an intrusive patch, not suitable for a
> > > > fix. Wire DPU_DEBUG and DPU_DEBUG_DRIVER to always use DRM_DEBUG_DRIVER
> > > > to make sure that DPU debugging messages always end up in the drm debug
> > > > messages and are controlled via the usual drm.debug mask.
> > > > 
> > > 
> > > These macros have been deprecated, is this waht you meant by the
> > > conversion to proper drm_debug_*?
> > 
> > Yes. Drop the driver-specific wrappers where they don't make sense.
> > Use sensible format strings in the cases where it actually does (like
> > VIDENC or _PLANE)
> > 
> 
> Ack but we need to not just drop the wrappers but drop the usage of these
> macros as well because it is documented that they are deprecated.
> 
> So I assume you want to get this in and do that as a follow up change?

Yes, somewhere in the long list of cleanups. I have a similar item
against DP driver, which uses correct macros, 

> > > /* NOTE: this is deprecated in favor of drm_dbg(NULL, ...). */
> > > #define DRM_DEBUG_DRIVER(fmt, ...)                                      \
> > >           __drm_dbg(DRM_UT_DRIVER, fmt, ##__VA_ARGS__)
> > > 
> > > I think all that this macro was doing was to have appropriate DRM_UT_*
> > > macros enabled before calling the corresponding DRM_DEBUG_* macros. But
> > > I think what was incorrect here is for DPU_DEBUG, we could have used
> > > DRM_UT_CORE instead of DRM_UT_KMS.
> > 
> > It pretty much tries to overplay the existing drm debugging mechanism
> > by either sending the messages to the DRM channel or just using
> > pr_debug. With DYNAMIC_DEBUG being disabled pr_debug is just an empty
> > macro, so all the messages can end up in /dev/null. We should not be
> > trying to be too smart, using standard DRM_DEBUG_DRIVER should be
> > enough. This way all driver-related messages are controlled by
> > drm.debug including or excluding the 0x02 bit.
> > 
> > 
> > > 
> > > And DRM_DEBUG_DRIVER should have been used instead of DRM_ERROR.
> > > 
> > > Was this causing the issue of the prints not getting enabled?
> > 
> > I pretty much think so.
> > 
> 
> Alright, I am okay with the approach, just one minor suggestion, to keep the
> behavior intact, previously the code wanted DPU_DEBUG to be controlled by
> DRM_UT_KMS and DPU_DEBUG_DRIVER controlled by DRM_UT_DRIVER.
> 
> Keeping that intact, we need to use DRM_DEBUG_KMS for DPU_DEBUG?

I might make that more explicit: I don't think that it is a good idea
for a generic DPU_DEBUG macro to be tied to DRM_UT_KMS. We are reporting
a debug message from driver, so by default it should go to the
DRM_UT_DRIVER channel. While refactoring things we might end up with
messages going to ATOMIC or KMS, but DRIVER should be the default.