[PATCH 0/4] drm/msm/dp: ST_DISPLAY_OFF hpd cleanup

[Dmitry Baryshkov]

On Mon, Dec 02, 2024 at 04:38:59PM -0800, Abhinav Kumar wrote:
> HPD state machine in msm dp display driver manages the state transitions
> between various HPD events and the expected state of driver to make sure
> both match up.
> 
> Although originally done with the intent of managing userspace interactions
> and interactions with compliance equipment, over period of time,
> changes to this piece of code has become quite difficult to manage.
> 
> Although, unwinding this logic will take some time and will be spread over
> various changes, to start things, this series tries to get rid of the
> ST_DISPLAY_OFF state as firstly, its really not an hpd state but a state
> of the display overall. Coupled with this, there are quite a few checks
> in the current code, the origins of which need to be re-visited OR are unclear
> which seem unlikely or redundant. With DP controller on newer chipsets supporting
> multiple streams, this has become increasingly difficult to work with.
> 
> This series removes the redundant state checks and simplifies the logic as an
> attempt to get rid of this ST_DISPLAY_OFF state.
> 
> Note: This series has been tested with sa8775p and sc7180 devices with multiple
> monitors and also multiple dongles with no noticeable regressions.
> Both of these devices use native DP PHY though. Hence, if this series can
> be verified on some devices with USBC-DP combo PHY with the help of the other
> developers, that will be great.

Don't you also have an RB5 (for pmic-typec) and SM83(?)50-HDK for
pmic-glink?

What kind of userspace were you testing with? Have you tested pure fbcon
/ drm_client?

> 
> To: Rob Clark <robdclark at gmail.com>
> To: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
> To: Sean Paul <sean at poorly.run>
> To: Marijn Suijten <marijn.suijten at somainline.org>
> To: David Airlie <airlied at gmail.com>
> To: Simona Vetter <simona at ffwll.ch>
> Cc: linux-arm-msm at vger.kernel.org
> Cc: dri-devel at lists.freedesktop.org
> Cc: freedreno at lists.freedesktop.org
> Cc: Stephen Boyd <swboyd at chromium.org>
> Cc: Doug Anderson <dianders at chromium.org>
> Cc: Johan Hovold <johan at kernel.org>
> Cc: Bjorn Andersson <quic_bjorande at quicinc.com>
> 
> Signed-off-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
> ---
> Abhinav Kumar (4):
>       drm/msm/dp: remove redundant checks related to ST_DISPLAY_OFF in plug/irq_ipd handlers
>       drm/msm/dp: remove redundant ST_DISPLAY_OFF checks in msm_dp_bridge_atomic_enable()
>       drm/msm/dp: replace ST_DISPLAY_OFF with power_on in msm_dp_hpd_unplug_handle()
>       drm/msm/dp: remove ST_DISPLAY_OFF as a hpd_state
> 
>  drivers/gpu/drm/msm/dp/dp_display.c | 23 ++---------------------
>  1 file changed, 2 insertions(+), 21 deletions(-)
> ---
> base-commit: 798bb342e0416d846cf67f4725a3428f39bfb96b
> change-id: 20241202-hpd_display_off-6051aa510f23
> 
> Best regards,
> -- 
> Abhinav Kumar <quic_abhinavk at quicinc.com>
> 

-- 
With best wishes
Dmitry