Re: [PATCH v8 drm-dp 1/4] drm/hisilicon/hibmc: fix dp probabilistical detect errors after HPD irq
From: Dmitry Baryshkov
Date: Wed Oct 08 2025 - 17:40:33 EST
On Fri, Sep 26, 2025 at 09:14:57AM +0800, Yongbang Shi wrote:
> From: Baihan Li <libaihan@xxxxxxxxxx>
>
> The issue is that drm_connector_helper_detect_from_ddc() returns wrong
> status when plugging or unplugging the monitor. Use HPD pin status in
> DP's detect_ctx() for real physcal monitor in/out, and implementation
> a complete DP detection including read DPCD, check if it's a branch
> device and its sink count for different situations.
>
> Fixes: 3c7623fb5bb6 ("drm/hisilicon/hibmc: Enable this hot plug detect of irq feature")
> Signed-off-by: Baihan Li <libaihan@xxxxxxxxxx>
> Signed-off-by: Yongbang Shi <shiyongbang@xxxxxxxxxx>
> ---
> ChangeLog:
> v7 -> v8:
> - fix build errors reported by kernel test robot <lkp@xxxxxxxxx>
> Closes: https://lore.kernel.org/oe-kbuild-all/202509241625.o4mNleVb-lkp@xxxxxxxxx/
> v6 -> v7:
> - add the check about branch devices, suggested by Dmitry Baryshkov.
> v5 -> v6:
> - use HPD status in DP detect_ctx(), suggested by Dmitry Baryshkov.
> v4 -> v5:
> - fix the commit message and DP detect_ctx(), suggested by Dmitry Baryshkov.
> ---
> drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h | 4 ++
> drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c | 12 +++++
> drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.h | 6 +++
> drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h | 3 ++
> .../gpu/drm/hisilicon/hibmc/hibmc_drm_dp.c | 48 ++++++++++++++++++-
> 5 files changed, 71 insertions(+), 2 deletions(-)
>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>
--
With best wishes
Dmitry