Maybe someone more familiar with the generic drm fbdev helpers can help me understand why they don't work with hibernation, at least with AMD GPUs. We converted amdgpu to use the generic helpers instead of rolling our own in this patch[1], but it seems to have broken hibernation[2]. amdgpu has always set mode_config.prefer_shadow = 1, but that seems to be the cause of the hibernation breakage with the generic helpers. I've been staring at the code for a while now but I can't see why this fails. Any pointers?
Thanks,
Alex
[1] - https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... [2] - https://bugzilla.kernel.org/show_bug.cgi?id=216119
Hi
Am 21.06.22 um 00:02 schrieb Alex Deucher:
Maybe someone more familiar with the generic drm fbdev helpers can help me understand why they don't work with hibernation, at least with AMD GPUs. We converted amdgpu to use the generic helpers instead of rolling our own in this patch[1], but it seems to have broken hibernation[2]. amdgpu has always set mode_config.prefer_shadow = 1, but that seems to be the cause of the hibernation breakage with the generic helpers. I've been staring at the code for a while now but I can't see why this fails. Any pointers?
I don't the actual reason, but when I tried to convert radeon to generic fbdev emulation, I had to modify the fbdev code a bit. I don't see how this would apply to amdgpu, but you can find the patchset attached. See patches 1 and 2.
Best regards Thomas
Thanks,
Alex
[1] - https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... [2] - https://bugzilla.kernel.org/show_bug.cgi?id=216119
Thanks Thomas. I think this got me on the right track.
Alex
On Tue, Jun 21, 2022 at 6:25 AM Thomas Zimmermann tzimmermann@suse.de wrote:
Hi
Am 21.06.22 um 00:02 schrieb Alex Deucher:
Maybe someone more familiar with the generic drm fbdev helpers can help me understand why they don't work with hibernation, at least with AMD GPUs. We converted amdgpu to use the generic helpers instead of rolling our own in this patch[1], but it seems to have broken hibernation[2]. amdgpu has always set mode_config.prefer_shadow = 1, but that seems to be the cause of the hibernation breakage with the generic helpers. I've been staring at the code for a while now but I can't see why this fails. Any pointers?
I don't the actual reason, but when I tried to convert radeon to generic fbdev emulation, I had to modify the fbdev code a bit. I don't see how this would apply to amdgpu, but you can find the patchset attached. See patches 1 and 2.
Best regards Thomas
Thanks,
Alex
[1] - https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... [2] - https://bugzilla.kernel.org/show_bug.cgi?id=216119
-- 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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