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Message-ID: <45shie2h45zmrrgtkt5k4v5hb7cjspjkdfugy3mvsjsbeggrm5@mfyhk5ntwmqe>
Date: Sat, 9 Aug 2025 10:10:26 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Jessica Zhang <jessica.zhang@....qualcomm.com>
Cc: Rob Clark <robin.clark@....qualcomm.com>,
Abhinav Kumar <abhinav.kumar@...ux.dev>,
Dmitry Baryshkov <lumag@...nel.org>, Sean Paul <sean@...rly.run>,
Marijn Suijten <marijn.suijten@...ainline.org>,
David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
Kuogee Hsieh <quic_khsieh@...cinc.com>, linux-arm-msm@...r.kernel.org,
dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org,
linux-kernel@...r.kernel.org, Yongxing Mou <quic_yongmou@...cinc.com>,
Abhinav Kumar <quic_abhinavk@...cinc.com>
Subject: Re: [PATCH v2 09/12] drm/msm/dp: remove redundant checks related to
ST_DISPLAY_OFF in plug handler
On Fri, Aug 08, 2025 at 05:35:21PM -0700, Jessica Zhang wrote:
> From: Abhinav Kumar <quic_abhinavk@...cinc.com>
>
> In commit 8ede2ecc3e5ee ("drm/msm/dp: Add DP compliance tests on Snapdragon
> Chipsets"), checks were introduced to avoid handling any plug event in
> ST_DISPLAY_OFF state.
>
> Even if we do get hpd events, after the bridge was disabled,
> it should get handled. Moreover, its unclear under what circumstances
> these events will fire because ST_DISPLAY_OFF means that the link was
> still connected but only the bridge was disabled. If the link was
> untouched, then interrupts shouldn't fire.
>
> Even in the case of the DP compliance equipment, it should be raising these
> interrupts during the start of the test which is usually accompanied with
> either a HPD pulse or a IRQ HPD but after the bridge is disabled it should
> be fine to handle these anyway. In the absence of a better reason to keep
> these checks, drop these and if any other issues do arise, it should be
> handled in a different way.
>
> Signed-off-by: Abhinav Kumar <quic_abhinavk@...cinc.com>
> Signed-off-by: Jessica Zhang <jessica.zhang@....qualcomm.com>
> ---
> Note: Taken from https://patchwork.freedesktop.org/series/142010/
> ---
> drivers/gpu/drm/msm/dp/dp_display.c | 3 ---
> 1 file changed, 3 deletions(-)
I think this patch and the next one should be folded into the 'drop the
HPD state machine' patch. It would be easier to review.
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> index eabd6e6981fb..dd3fdeaacc91 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> @@ -495,9 +495,6 @@ static int msm_dp_hpd_plug_handle(struct msm_dp_display_private *dp, u32 data)
> drm_dbg_dp(dp->drm_dev, "Before, type=%d hpd_state=%d\n",
> dp->msm_dp_display.connector_type, state);
>
> - if (state == ST_DISPLAY_OFF)
> - return 0;
> -
> if (state == ST_MAINLINK_READY || state == ST_CONNECTED)
> return 0;
>
>
> --
> 2.50.1
>
--
With best wishes
Dmitry
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