On Thu, Jul 17, 2025 at 11:36:38PM +0200, Jérôme de Bretagne wrote: > Le jeu. 17 juil. 2025 à 23:10, Konrad Dybcio > <konrad.dyb...@oss.qualcomm.com> a écrit : > > > > On 7/17/25 10:27 PM, Jérôme de Bretagne wrote: > > > On 2025/7/17 04:21, Xilin Wu <sop...@radxa.com> wrote : > > >> > > >> On 2025/7/15 01:35:42, Dale Whinham wrote: > > >>> From: Jérôme de Bretagne <jerome.debreta...@gmail.com> > > >>> > > >>> The OLED display in the Surface Pro 11 reports a maximum link rate of > > >>> zero in its DPCD, causing it to fail to probe correctly. > > >>> > > >>> The Surface Pro 11's DSDT table contains some XML with an > > >>> "EDPOverrideDPCDCaps" block that defines the max link rate as 0x1E > > >>> (8.1Gbps/HBR3). > > >>> > > >>> Add a quirk to conditionally override the max link rate if its value > > >>> is zero specifically for this model. > > >>> > > >>> Signed-off-by: Jérôme de Bretagne <jerome.debreta...@gmail.com> > > >>> Signed-off-by: Dale Whinham <dal...@gmail.com> > > >>> --- > > >>> drivers/gpu/drm/msm/dp/dp_panel.c | 13 +++++++++++++ > > >>> 1 file changed, 13 insertions(+) > > >>>
[...] > > > > > > > Is it a feature planned in the short-medium term within the MSM driver? > > > If not, would a quirk like [4] be acceptable upstream in the meanwhile? > > > > I'm not a display guy, but this looks like yet another block of code > > begging to be commonized across DP drivers, > > I agree 100% in principle, but the 3 implementations are different today. > > > so I wouldn't expect it to be a big blocker. > > Well, it is for me :) > > > Adding a panel quirk doesn't seem in order, as the panel is /probably/ > > very much in spec, and it's the driver bit that's missing. > > I agree that a quirk shouldn't be needed. I guess we'll work on > upstreaming everything else and keep an out-of-tree patch for this > issue for the moment That's a bit sad as this will block regular > users from easily installing / testing via the Ubuntu Concept ISO > for instance. > > Or could the quirk be accepted temporarily with good comments > then reverted when the driver adds the missing support? I guess > it would depend on the time scale of this support landing. Unforutunately, there is more than that. We should also be writing the LINK_RATE_SET register. So, just setting the max_bw is not enough. -- With best wishes Dmitry
