[PATCH] PM: Restrict swap use to later in the suspend sequence

[Lucian Langa]

On 13.06.2025 16:43, Mario Limonciello wrote:
> From: Mario Limonciello <mario.limonciello at amd.com>
> 
> Currently swap is restricted before drivers have had a chance to do their
> prepare() PM callbacks. Restricting swap this early means that if a driver
> needs to evict some content from memory into sawp in it's prepare callback
> it won't be able to.
> 
> On AMD dGPUs this can lead to failed suspends under memory pressure
> situations as all VRAM must be evicted to system memory or swap.
> 
> Move the swap restriction to right after all devices have had a chance to
> do the prepare() callback.  If there is any problem with the sequence,
> restore swap in the appropriate dpm resume callbacks or error handling
> paths.
> 
> Closes: https://github.com/ROCm/ROCK-Kernel-Driver/issues/174
> Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/2362
> Signed-off-by: Mario Limonciello <mario.limonciello at amd.com>

Tested this against 6.15.3 and 6.16-rc3.
Adding my tag.

Tested-by: Lucian Langa <lucilanga at 7pot.org>