Hi Am 25.10.22 um 09:12 schrieb Jeremy Rand:
Hi dri-devel,I have two machines with ASPEED GPU's (ast Linux driver). One machine is x86_64, running an ASRock Rack Tommy 90-SC02P1-00UBNZ GPU (AST2510 chipset) with KDE Plasma Wayland; the other is ppc64le, running an integrated AST2500 GPU with KDE Plasma X11. Both the AST2510 and AST2500 have 16 MiB VRAM according to lspci. Both ASPEED GPU's are advertised as supporting up to 1920x1200 resolution, but KDE only detects a maximum resolution of 1920x1080.Some additional information about this bug can be found at https://forums.raptorcs.com/index.php/topic,31.0.html .I believe this is a Linux bug, because it is solely dependent on the Linux version. The following Linux versions are confirmed to have the bug:Debian: 5.6.0-1 (ppc64el) Fedora: 5.6.0-1.fc33.x86_64 5.6.0-1.fc33.ppc64le 5.17.5-300.fc36.x86_64 5.18.6-200.fc36.ppc64le 6.1.0-0.rc0.20221007git4c86114194e6.5.fc38.ppc64leWhereas the following Linux versions are confirmed to work fine (max resolution detected by KDE is 1920x1200 as it should be, and that resolution works fine when selected):Debian: 5.5.0-2 (ppc64el) Fedora: 5.5.17-200.fc31.x86_64 5.5.17-200.fc31.ppc64leI believe the bug was introduced by Linux commit 9253f830c9166bfa6cc07d5ed59e174e9d5ec6ca, which adds a VRAM size check that assumes double-buffering. 1920x1080 resolution at 4 bytes per pixel with 2 buffers is 16.6 MB, while bumping that to 1920x1200 results in 18.4 MB. Since the VRAM size is 16 MiB == 16.8 MB, that explains the issue.
Thanks for reporting. It's been a known issue for a while.But in the most recent devel tree, we have replaced ast memory management, so that it can now use the full vram size for scanout buffers. See
https://cgit.freedesktop.org/drm/drm-tip/commit/drivers/gpu/drm/ast/ast_mode.c?id=f2fa5a99ca81ce1056539e83c705f3d6bec62e31 To test, get the latest drm-tip from git://anongit.freedesktop.org/drm/drm-tip and try on your machine. The updated driver should become available in Linux v6.3. Best regards Thomas
Steps to reproduce:* Add a GPU that uses the ast driver, which supports 1920x1200 resolution and has 16 MiB VRAM.* Boot into KDE.* Go to KDE System Settings -> Display and Monitor -> Display Configuration.* Look at list of detected resolutions. * KDE will only detect up to 1920x1080 resolution.I'm attaching the output of "journalctl --no-hostname -k", although I'm doubtful that anything useful is in the log.I reported this bug to Fedora at https://bugzilla.redhat.com/show_bug.cgi?id=2136950 , and was directed to this mailing list.Happy to provide more details on request. (I'm not subscribed to this list, so please CC any replies to me.)Cheers,
-- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Ivo Totev
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