<div dir="ltr"><div>Applied to kinetic linux master-next</div><div> </div><div>Thanks,</div><div> </div><div>- Luke </div> <div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Apr 20, 2023 at 2:22 AM Matthew Ruffell <<a href="mailto:matthew.ruffell@canonical.com">matthew.ruffell@canonical.com</a>> wrote: </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">BugLink: <a href="https://bugs.launchpad.net/bugs/2007001" rel="noreferrer" target="_blank">https://bugs.launchpad.net/bugs/2007001</a> [Impact] Numerous VMWare users have reported that vmwgfx cannot reserve the memory region for the graphics framebuffer, leading their VMs to have blank screens. They see the following in dmesg: [ 11.135360] vmwgfx 0000:00:0f.0: BAR 2: can't reserve [mem 0x70000000-0x77ffffff 64bit pref] [ 11.135366] vmwgfx: probe of 0000:00:0f.0 failed with error -16 And a cat /proc/iomem shows this: 50000000-7fffffff : PCI Bus 0000:00 70000000-77ffffff : 0000:00:0f.0 70000000-702fffff : BOOTFB The kernel has failed to release this memory region for vmwgfx to occupy. Most affected users are on aarch64, with the host being Apple silicon systems. [Fix] The regression was introduced by the below commit in 5.19.0-30-generic: commit 5e01376124309b4dbd30d413f43c0d9c2f60edea Author: Thomas Zimmermann <<a href="mailto:tzimmermann@suse.de" target="_blank">tzimmermann@suse.de</a>> Date: Mon Jul 18 09:23:18 2022 +0200 Subject: video/aperture: Disable and unregister sysfb devices via aperture helpers Link: <a href="https://github.com/torvalds/linux/commit/5e01376124309b4dbd30d413f43c0d9c2f60edea" rel="noreferrer" target="_blank">https://github.com/torvalds/linux/commit/5e01376124309b4dbd30d413f43c0d9c2f60edea</a> This commit was part of a larger refactoring of the video subsystem, and requires the entire series to function correctly. You can review the whole series below: <a href="https://patchwork.freedesktop.org/series/106040/" rel="noreferrer" target="_blank">https://patchwork.freedesktop.org/series/106040/</a> The patch series also requires quite a few additional fixups to fix bugs introduced by the series, making the size about 15 commits in total. The contents of the series don't really fix any bugs, and their purpose is to refactor the code for future changes to the fbdev subsystem, and really aren't appropriate to be backported to a stable kernel series. "video/aperture: Disable and unregister sysfb devices via aperture helpers" seems to have been selected for -stable by mistake by its fixes: tag, and was pulled into upstream stable by a robot with little human review. The best course of action is to revert. No action needed for Lunar, as the entire series is present in that release. [Testcase] This bug affects users running Ubuntu in VMWare VMs, notably on aarch64 devices, like modern Apple computers. Start a Kinetic or Jammy-HWE Server or Desktop VM in VMWare Fusion on Apple silicon, and see if the display comes up or not. Affected users will see a blank screen. There is a test kernel available in the following ppa: <a href="https://launchpad.net/~mruffell/+archive/ubuntu/lp2007001-test" rel="noreferrer" target="_blank">https://launchpad.net/~mruffell/+archive/ubuntu/lp2007001-test</a> If you install the test kernel and reboot, you will be able to see the screen on your VM like normal. [Where problems could occur] This commit changes when the sysfb is disabled and memory region for the graphics framebuffer is released to the proper device driver. If a regression were to occur, then graphics drivers may fail to reserve the framebuffer memory, and fail to start, leaving users with a blank screen. There are no workarounds, other than booting a previous kernel. Matthew Ruffell (1): UBUNTU: SAUCE: Revert "video/aperture: Disable and unregister sysfb devices via aperture helpers" drivers/gpu/drm/drm_aperture.c | 14 -------------- drivers/video/fbdev/core/fbmem.c | 12 ++++++++++++ 2 files changed, 12 insertions(+), 14 deletions(-) -- 2.39.2 -- kernel-team mailing list <a href="mailto:kernel-team@lists.ubuntu.com" target="_blank">kernel-team@lists.ubuntu.com</a> <a href="https://lists.ubuntu.com/mailman/listinfo/kernel-team" rel="noreferrer" target="_blank">https://lists.ubuntu.com/mailman/listinfo/kernel-team</a> </blockquote></div></div>