+ dri-devel On Mon, Apr 25, 2022 at 3:33 AM Krylov Michael <sqarert@xxxxxxxxx> wrote: > > Hello! > > After updating my Linux kernel from version 4.19 (Debian 10 version) to > 5.10 (packaged with Debian 11), I've noticed that the image > displayed on my older computer, 32-bit Pentium 4 using ATI Radeon X1950 > AGP video card is severely corrupted in the graphical (Xorg and Wayland) > mode: all kinds of black and white stripes across the screen, some > letters missing, etc. > > I've checked several options (Xorg drivers, Wayland instead of > Xorg, radeon.agpmode=-1 in kernel command line and so on), but the > problem persisted. I've managed to find that the problem was in the > kernel, as everything worked well with 4.19 kernel with everything > else being from Debian 11. > > I have managed to find the culprit of that corruption, that is the > commit 33b3ad3788aba846fc8b9a065fe2685a0b64f713 on the linux kernel. > Reverting this commit and building the kernel with that commit reverted > fixes the problem. Disabling HIMEM also gets rid of that problem. But it > also leaves the system with less that 1G of RAM, which is, of course, > undesirable. > > Apparently this problem is somewhat known, as I can tell after googling > for the commit id, see this link for example: > https://lkml.org/lkml/2020/1/9/518 > > Mageia distro, for example, reverted this commit in the kernel they are > building: > > http://sophie.zarb.org/distrib/Mageia/7/i586/by-pkgid/b9193a4f85192bc57f4d770fb9bb399c/files/32 > > I've reported this bug to Debian bugtracker, checked the recent verion > of the kernel (5.17), bug still persists. Here's a link to the Debian > bug page: > > https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=993670 > > I'm not sure if reverting this commit is the correct way to go, so if > you need to check any changes/patches that I could apply and test on > the real hardware, I'll be glad to do that (but please keep in mind > that testing could take some time, I don't have access to this computer > 24/7, but I'll do my best to respond ASAP). I would be happy to revert that commit. I attempted to revert it a year or so ago, but Christoph didn't want to. He was going to look further into it. I was not able to repro the issue. It seemed to be related to highmem support. You might try disabling that. Here is the previous thread for reference: https://lists.freedesktop.org/archives/amd-gfx/2020-September/053922.html Alex
