On Tue, Oct 24, 2023 at 04:09:03AM +0300, Imre Deak wrote:
> Add a quirk for Synaptics MST hubs, which require a workaround - at leat
> on i915 - for some modes, on which the hub applies HBLANK expansion.
> These modes will only work by enabling DSC decompression for them, a
> follow-up patch will do this in i915.
>
> Cc: Lyude Paul <ly...@redhat.com>
> Signed-off-by: Imre Deak <imre.d...@intel.com>
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovs...@intel.com>
> ---
> drivers/gpu/drm/display/drm_dp_helper.c | 2 ++
> include/drm/display/drm_dp_helper.h | 7 +++++++
> 2 files changed, 9 insertions(+)
>
> diff --git a/drivers/gpu/drm/display/drm_dp_helper.c
> b/drivers/gpu/drm/display/drm_dp_helper.c
> index f3680f4e69708..e5d7970a9ddd0 100644
> --- a/drivers/gpu/drm/display/drm_dp_helper.c
> +++ b/drivers/gpu/drm/display/drm_dp_helper.c
> @@ -2245,6 +2245,8 @@ static const struct dpcd_quirk dpcd_quirk_list[] = {
> { OUI(0x00, 0x00, 0x00), DEVICE_ID('C', 'H', '7', '5', '1', '1'),
> false, BIT(DP_DPCD_QUIRK_NO_SINK_COUNT) },
> /* Synaptics DP1.4 MST hubs can support DSC without virtual DPCD */
> { OUI(0x90, 0xCC, 0x24), DEVICE_ID_ANY, true,
> BIT(DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD) },
> + /* Synaptics DP1.4 MST hubs require DSC for some modes on which it
> applies HBLANK expansion. */
> + { OUI(0x90, 0xCC, 0x24), DEVICE_ID_ANY, true,
> BIT(DP_DPCD_QUIRK_HBLANK_EXPANSION_REQUIRES_DSC) },
> /* Apple MacBookPro 2017 15 inch eDP Retina panel reports too low
> DP_MAX_LINK_RATE */
> { OUI(0x00, 0x10, 0xfa), DEVICE_ID(101, 68, 21, 101, 98, 97), false,
> BIT(DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS) },
> };
> diff --git a/include/drm/display/drm_dp_helper.h
> b/include/drm/display/drm_dp_helper.h
> index 3d74b2cec72fd..351f38d5cc351 100644
> --- a/include/drm/display/drm_dp_helper.h
> +++ b/include/drm/display/drm_dp_helper.h
> @@ -632,6 +632,13 @@ enum drm_dp_quirk {
> * the DP_MAX_LINK_RATE register reporting a lower max multiplier.
> */
> DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_3_24_GBPS,
> + /**
> + * @DP_DPCD_QUIRK_HBLANK_EXPANSION_NEEDS_DSC:
> + *
> + * The device applies HBLANK expansion for some modes, but this
> + * requires enabling DSC.
> + */
> + DP_DPCD_QUIRK_HBLANK_EXPANSION_REQUIRES_DSC,
> };
>
> /**
> --
> 2.39.2
>
