Re: [PATCH 3/5] drm/i915: Implement the intel_dp_autotest_edid function for DP EDID complaince tests

[Jani Nikula <jani.nikula@linux.intel.com>]

On Mon, 04 May 2015, Daniel Vetter <daniel@ffwll.ch> wrote:
> On Thu, Apr 30, 2015 at 03:30:10PM -0300, Paulo Zanoni wrote:
>> 2015-04-18 4:04 GMT-03:00 Todd Previte <tprevite@gmail.com>:
>> > Updates the EDID compliance test function to perform the analyze and react to
>> > the EDID data read as a result of a hot plug event. The results of this
>> > analysis are handed off to userspace so that the userspace app can set the
>> > display mode appropriately for the test result/response.
>> >
>> > The compliance_test_active flag now appears at the end of the individual
>> > test handling functions. This is so that the kernel-side operations can
>> > be completed without the risk of interruption from the userspace app
>> > that is polling on that flag.
>> >
>> > V2:
>> > - Addressed mailing list feedback
>> > - Removed excess debug messages
>> > - Removed extraneous comments
>> > - Fixed formatting issues (line length > 80)
>> > - Updated the debug message in compute_edid_checksum to output hex values
>> >   instead of decimal
>> > V3:
>> > - Addressed more list feedback
>> > - Added the test_active flag to the autotest function
>> > - Removed test_active flag from handler
>> > - Added failsafe check on the compliance test active flag
>> >   at the end of the test handler
>> > - Fixed checkpatch.pl issues
>> > V4:
>> > - Removed the checksum computation function and its use as it has been
>> >   rendered superfluous by changes to the core DRM EDID functions
>> > - Updated to use the raw header corruption detection mechanism
>> > - Moved the declaration of the test_data variable here
>> > V5:
>> > - Update test active flag variable name to match the change in the
>> >   first patch of the series.
>> > - Relocated the test active flag declaration and initialization
>> >   to this patch
>> > V6:
>> > - Updated to use the new flag for raw EDID header corruption
>> > - Removed the extra EDID read from the autotest function
>> > - Added the edid_checksum variable to struct intel_dp so that the
>> >   autotest function can write it to the sink device
>> > - Moved the update to the hpd_pulse function to another patch
>> > - Removed extraneous constants
>> > V7:
>> > - Fixed erroneous placement of the checksum assignment. In some cases
>> >   such as when the EDID read fails and is NULL, this causes a NULL ptr
>> >   dereference in the kernel. Bad news. Fixed now.
>> > V8:
>> > - Updated to support the kfree() on the EDID data added previously
>> > V9:
>> > - Updated for the long_hpd flag propagation
>> > V10:
>> > - Updated to use actual checksum from the EDID read that occurs during
>> >   normal hot plug path execution
>> > - Removed variables from intel_dp struct that are no longer needed
>> > - Updated the patch subject to more closely match the nature and contents
>> >   of the patch
>> >
>> > Signed-off-by: Todd Previte <tprevite@gmail.com>
>> > ---
>> >  drivers/gpu/drm/i915/intel_dp.c  | 41 ++++++++++++++++++++++++++++++++++++++++
>> >  drivers/gpu/drm/i915/intel_drv.h |  2 ++
>> >  2 files changed, 43 insertions(+)
>> >
>> > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
>> > index 55d1f5f..4c1f6a9 100644
>> > --- a/drivers/gpu/drm/i915/intel_dp.c
>> > +++ b/drivers/gpu/drm/i915/intel_dp.c
>> > @@ -41,6 +41,12 @@
>> >
>> >  #define DP_LINK_CHECK_TIMEOUT  (10 * 1000)
>> >
>> > +/* Compliance test status bits  */
>> > +#define INTEL_DP_RESOLUTION_SHIFT_MASK 4
>> 
>> Now that you cleaned all the other stuff, can't we start at 0 instead
>> of 4? (of course, this would require a change to the user space tool)
>> 
>> 
>> > +#define INTEL_DP_RESOLUTION_PREFERRED  (1 << INTEL_DP_RESOLUTION_SHIFT_MASK)
>> > +#define INTEL_DP_RESOLUTION_STANDARD   (2 << INTEL_DP_RESOLUTION_SHIFT_MASK)
>> > +#define INTEL_DP_RESOLUTION_FAILSAFE   (3 << INTEL_DP_RESOLUTION_SHIFT_MASK)
>> > +
>> >  struct dp_link_dpll {
>> >         int link_bw;
>> >         struct dpll dpll;
>> > @@ -3994,6 +4000,38 @@ static uint8_t intel_dp_autotest_video_pattern(struct intel_dp *intel_dp)
>> >  static uint8_t intel_dp_autotest_edid(struct intel_dp *intel_dp)
>> >  {
>> >         uint8_t test_result = DP_TEST_NAK;
>> > +       uint32_t ret = 0;
>> > +       struct intel_connector *intel_connector = intel_dp->attached_connector;
>> > +       struct drm_connector *connector = &intel_connector->base;
>> > +
>> > +       if (intel_connector->detect_edid == NULL ||
>> > +           connector->edid_corrupt == 1 ||
>> > +           intel_dp->aux.i2c_defer_count > 6) {
>> > +               /* Check for NACKs/DEFERs, use failsafe if detected
>> > +                *  (DP CTS 1.2 Core Rev 1.1, 4.2.2.4, 4.2.2.5)
>> > +                */
>> > +               if (intel_dp->aux.i2c_nack_count > 0 ||
>> > +                       intel_dp->aux.i2c_defer_count > 0)
>> > +                       DRM_DEBUG_KMS("EDID read had %d NACKs, %d DEFERs\n",
>> > +                                     intel_dp->aux.i2c_nack_count,
>> > +                                     intel_dp->aux.i2c_defer_count);
>> > +               intel_dp->compliance_test_data = INTEL_DP_RESOLUTION_FAILSAFE;
>> > +       } else {
>> > +               ret = drm_dp_dpcd_write(&intel_dp->aux,
>> > +                                       DP_TEST_EDID_CHECKSUM,
>> > +                                       &intel_connector->detect_edid->checksum, 1);
>> > +               if (ret <= 0)
>> > +                       DRM_DEBUG_DRIVER("Failed to write EDID checksum\n");
>> > +               else
>> > +                       DRM_DEBUG_DRIVER("EDID checksum written to sink\n");
>> 
>> You're mixing DRM_DEBUG_DRIVER and DRM_DEBUG_KMS. I'd stick with only
>> one, and I'd probably pick _KMS.
>> 
>> With or without the above bikesheds: Reviewed-by: Paulo Zanoni
>> <paulo.r.zanoni@intel.com>
>
> Yeah I second the two polish requests from Paulo. Merged the previous
> patch meanwhile.

I reverted this to unblock people because it breaks the build due to the
dependency on patch 2/5 which was apparently not merged yet. Sorry
Daniel, didn't get hold of you fast enough...

BR,
Jani.




> -Daniel
>
>> 
>> > +
>> > +               test_result = DP_TEST_ACK | DP_TEST_EDID_CHECKSUM_WRITE;
>> > +               intel_dp->compliance_test_data = INTEL_DP_RESOLUTION_STANDARD;
>> > +       }
>> > +
>> > +       /* Set test active flag here so userspace doesn't interrupt things */
>> > +       intel_dp->compliance_test_active = 1;
>> > +
>> >         return test_result;
>> >  }
>> >
>> > @@ -4009,7 +4047,10 @@ static void intel_dp_handle_test_request(struct intel_dp *intel_dp)
>> >         uint8_t rxdata = 0;
>> >         int status = 0;
>> >
>> > +       intel_dp->compliance_test_active = 0;
>> >         intel_dp->compliance_test_type = 0;
>> > +       intel_dp->compliance_test_data = 0;
>> > +
>> >         intel_dp->aux.i2c_nack_count = 0;
>> >         intel_dp->aux.i2c_defer_count = 0;
>> >
>> > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>> > index a4675fa..6c71be9 100644
>> > --- a/drivers/gpu/drm/i915/intel_drv.h
>> > +++ b/drivers/gpu/drm/i915/intel_drv.h
>> > @@ -742,6 +742,8 @@ struct intel_dp {
>> >
>> >         /* Displayport compliance testing */
>> >         unsigned long compliance_test_type;
>> > +       unsigned long compliance_test_data;
>> > +       bool compliance_test_active;
>> >  };
>> >
>> >  struct intel_digital_port {
>> > --
>> > 1.9.1
>> >
>> > _______________________________________________
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>> > Intel-gfx@lists.freedesktop.org
>> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>> 
>> 
>> 
>> -- 
>> Paulo Zanoni
>> _______________________________________________
>> Intel-gfx mailing list
>> Intel-gfx@lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
> _______________________________________________
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> Intel-gfx@lists.freedesktop.org
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-- 
Jani Nikula, Intel Open Source Technology Center
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