linux-kernel - [PATCH v2 0/4] drm/msm/dp: Improve DP AUX transfer vs. HPD interactions

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Date: Fri, 15 Mar 2024 14:36:28 -0700
From: Douglas Anderson <dianders@...omium.org>
To: Rob Clark <robdclark@...il.com>,
	Abhinav Kumar <quic_abhinavk@...cinc.com>,
	Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc: Douglas Anderson <dianders@...omium.org>,
	Bjorn Andersson <quic_bjorande@...cinc.com>,
	Daniel Vetter <daniel@...ll.ch>,
	David Airlie <airlied@...il.com>,
	Guenter Roeck <groeck@...omium.org>,
	Kuogee Hsieh <quic_khsieh@...cinc.com>,
	Marijn Suijten <marijn.suijten@...ainline.org>,
	Sean Paul <sean@...rly.run>,
	Stephen Boyd <swboyd@...omium.org>,
	Vara Reddy <quic_varar@...cinc.com>,
	dri-devel@...ts.freedesktop.org,
	freedreno@...ts.freedesktop.org,
	linux-arm-msm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2 0/4] drm/msm/dp: Improve DP AUX transfer vs. HPD interactions


The main goal of this patch series is to avoid problems running
"fwupd" on Qualcomm devices. Right now several of the plugins used
with fwupd try talking over all DP AUX busses and this results in a
very long timeout on Qualcomm devices.

As part of fixing this, I noticed a case where the MSM DP code wasn't
respecing the timeout properly when asked to wait for HPD. I also
noticed that, now that we've implemented wait_hpd_asserted(), we no
longer need the long hardcoded timeout / special case for eDP in the
AUX transfer function.

NOTE: I managed to dig up some hardware to test the eDP case and my
basic testing shows that everything still works fine there after this
series.

Changes in v2:
- Don't look at the HPD line directly; have dp_display call us.
- ("Fix typo in static function (ststus => status)") new for v2.

Douglas Anderson (4):
  drm/msm/dp: Avoid a long timeout for AUX transfer if nothing connected
  drm/msm/dp: Account for the timeout in wait_hpd_asserted() callback
  drm/msm/dp: Delete the old 500 ms wait for eDP HPD in aux transfer
  drm/msm/dp: Fix typo in static function (ststus => status)

 drivers/gpu/drm/msm/dp/dp_aux.c     | 30 ++++++++++++++++-------------
 drivers/gpu/drm/msm/dp/dp_aux.h     |  1 +
 drivers/gpu/drm/msm/dp/dp_catalog.c |  7 ++++---
 drivers/gpu/drm/msm/dp/dp_catalog.h |  3 ++-
 drivers/gpu/drm/msm/dp/dp_display.c |  8 ++++++--
 5 files changed, 30 insertions(+), 19 deletions(-)

-- 
2.44.0.291.gc1ea87d7ee-goog