On Mon, Dec 01, 2025 at 01:14:46AM +0000, Dale Whinham wrote: > From: Jérôme de Bretagne <[email protected]> > > The Samsung ATNA30DW01-1 OLED panel in Microsoft Surface Pro 11 (Denali) > reports a max link rate value of 0 in the DPCD register, causing the > panel to fail to probe. > > Add a quirk for this panel during DPCD read to set the max link rate > to 8.1Gbps (HBR3), which is the expected value as reported by the > "EDPOverrideDPCDCaps" block found in the DSDT (0x1E). > > Signed-off-by: Jérôme de Bretagne <[email protected]> > Tested-by: Dale Whinham <[email protected]> > --- > drivers/gpu/drm/display/drm_dp_helper.c | 2 ++ > drivers/gpu/drm/msm/dp/dp_panel.c | 14 ++++++++++++++ > include/drm/display/drm_dp_helper.h | 7 +++++++ > 3 files changed, 23 insertions(+) > > diff --git a/drivers/gpu/drm/display/drm_dp_helper.c > b/drivers/gpu/drm/display/drm_dp_helper.c > index 4aaeae4fa03c..a533fbb2988d 100644 > --- a/drivers/gpu/drm/display/drm_dp_helper.c > +++ b/drivers/gpu/drm/display/drm_dp_helper.c > @@ -2543,6 +2543,8 @@ static const struct dpcd_quirk dpcd_quirk_list[] = { > { OUI(0x00, 0x0C, 0xE7), DEVICE_ID_ANY, false, > 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) }, > + /* Samsung ATNA30DW01-1 OLED panel in Microsoft Surface Pro 11 reports > a DP_MAX_LINK_RATE of 0 */ > + { OUI(0xBA, 0x41, 0x59), DEVICE_ID_ANY, false, > BIT(DP_DPCD_QUIRK_CAN_DO_MAX_LINK_RATE_8_1_GBPS) },
NAK, DP_MAX_LINK_RATE = 0 is a part of the eDP standard. The driver should use alternative method (Link Rate Table) to identify supported link rates. > }; > > #undef OUI -- With best wishes Dmitry
