[Intel-gfx] [PATCH] drm/i915: preserve other DP_TEST_SINK bits.

[Daniel Vetter]

On Tue, Sep 30, 2014 at 01:41:20PM -0700, Rodrigo Vivi wrote:
> Please don't forget the drm/i915: Fix Sink CRC
> 
> That is the important one that fix crc calculation and will allow me
> to remove the extra wait for vblanks on tests besides making tests
> more stable.
> 
> 
> On Tue, Sep 30, 2014 at 1:36 PM, Daniel Vetter <daniel at ffwll.ch> wrote:
> > On Mon, Sep 29, 2014 at 06:29:52PM -0400, Rodrigo Vivi wrote:
> >> Sink crc was implemented based on dp 1.1 spec that had all TEST_SINK bits
> >> reserved reading all 0s. But when reviewing my latest changes on sink crc
> >> Todd warned me that on new specs we have other valid bits on this reg that we
> >> might want to preserve.
> >>
> >> Cc: Todd Previte <tprevite at gmail.com>
> >> Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> >> ---
> >>  drivers/gpu/drm/i915/intel_dp.c | 8 ++++++--
> >>  1 file changed, 6 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> >> index b8699b0..7d5fa2f 100644
> >> --- a/drivers/gpu/drm/i915/intel_dp.c
> >> +++ b/drivers/gpu/drm/i915/intel_dp.c
> >> @@ -3821,8 +3821,9 @@ int intel_dp_sink_crc(struct intel_dp *intel_dp, u8 *crc)
> >>       if (!(buf & DP_TEST_CRC_SUPPORTED))
> >>               return -ENOTTY;
> >>
> >> +     drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_SINK, &buf);
> >>       if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_TEST_SINK,
> >
> > With this we no longer check the first aux transaction for errors, and
> > maybe we should even check them all?
> 
> That is true. Do you prefer a v2 or top fix?
> And what do you prefer? avoid the check at all or check on the first
> aux transaction?

Fixup patch is ok, I've kept your patch here. And I guess if you bother
you should add checks with return -EIO to all of them, since they could
all fail. Even if it's just for consistency.
-Daniel

> 
> 
> > -Daniel
> >
> >> -                            DP_TEST_SINK_START) < 0)
> >> +                             buf | DP_TEST_SINK_START) < 0)
> >>               return -EIO;
> >>
> >>       drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_SINK_MISC, &buf);
> >> @@ -3841,7 +3842,10 @@ int intel_dp_sink_crc(struct intel_dp *intel_dp, u8 *crc)
> >>       if (drm_dp_dpcd_read(&intel_dp->aux, DP_TEST_CRC_R_CR, crc, 6) < 0)
> >>               return -EIO;
> >>
> >> -     drm_dp_dpcd_writeb(&intel_dp->aux, DP_TEST_SINK, 0);
> >> +     drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_SINK, &buf);
> >> +     drm_dp_dpcd_writeb(&intel_dp->aux, DP_TEST_SINK,
> >> +                     buf & ~DP_TEST_SINK_START);
> >> +
> >>       return 0;
> >>  }
> >>
> >> --
> >> 1.9.3
> >>
> >> _______________________________________________
> >> Intel-gfx mailing list
> >> Intel-gfx at lists.freedesktop.org
> >> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> >
> > --
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > +41 (0) 79 365 57 48 - http://blog.ffwll.ch
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> 
> 
> -- 
> Rodrigo Vivi
> Blog: http://blog.vivi.eng.br

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch