On Sat, Aug 17, 2024 at 10:30:41PM +0200, Kevin Holm wrote:
On 17.08.24 10:42, Greg KH wrote:
On Tue, Jul 30, 2024 at 08:53:39PM +0200, Kevin Holm wrote:
From: Wayne Lin wayne.lin@amd.com
[ Upstream commit fa57924c76d995e87ca3533ec60d1d5e55769a27 ]
[Why] dm_dp_mst_is_port_support_mode() is a bit not following the original design rule and cause light up issue with multiple 4k monitors after mst dsc hub.
[How] Refactor function dm_dp_mst_is_port_support_mode() a bit to solve the light up issue.
Reviewed-by: Jerry Zuo jerry.zuo@amd.com Acked-by: Zaeem Mohamed zaeem.mohamed@amd.com Signed-off-by: Wayne Lin wayne.lin@amd.com Tested-by: Daniel Wheeler daniel.wheeler@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com [kevin@holm.dev: Resolved merge conflict in .../amdgpu_dm_mst_types.c] Fixes: 4df96ba6676034 ("drm/amd/display: Add timing pixel encoding for mst mode validation") Link: https://lore.kernel.org/stable/d74a7768e957e6ce88c27a5bece0c64dff132e24@holm... Signed-off-by: Kevin Holm kevin@holm.dev
I resolved the merge conflict so that, after this patch is applied to the linux-6.10.y branch of the stable git repository, the resulting function dm_dp_mst_is_port_support_mode (and also the new function dp_get_link_current_set_bw) is identical to the original commit.
I've confirmed that it fixes the regression I reported for my use case.
And it turns out this change breaks the arm and arm64 builds. I tried to fix it up by applying the fixup afterward for this file, but it's just too much of a mess to unwind this, so I'm going to have to revert this now, sorry.
That sucks, sorry for the problems my patch caused. :(
See: https://lore.kernel.org/r/b27c5434-f1b1-4697-985b-91bb3e9a22df@roeck-us.net for details.
I unfortunately don't know the amdgpu driver and kernel code in general enough to help fix that. The back-ported patch I send was my first patch to the kernel.
In the email thread where I reported the problem I send a patch that reverts 4df96ba6676034 ("drm/amd/display: Add timing pixel encoding for mst mode validation") to fix the problem that way [1]. I've included a copy of that below. I've tested that it still applies to 6.10.6-rc3 without conflicts and compiles for me. I could not test if the 6.10.6-rc3 with the revert applied fixes the problem as I'm traveling and don't have access to my normal setup. I can only say that reverting it on v6.10.2 fixed the problem for me.
I don't know how to compile for other architectures so I did not test that.
Not sure what would be best, reverting the problem commit so the regression is fixed in the 6.10 stable kernel (and maybe breaking something else?) or waiting for someone at AMD with better knowledge of the amdgpu driver to back-port the fixing commit in a non-broken way.
Yes, this is up to the amd developers now, I suggest you work with them to get this resolved please.
Or just use 6.11-rc3 and newer :)
thanks,
greg k-h