This is a note to let you know that I've just added the patch titled
drm/radeon: avoid bogus "vram limit (0) must be a power of 2" warning
to the 5.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-radeon-avoid-bogus-vram-limit-0-must-be-a-power-.patch
and it can be found in the queue-5.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 141b5cb5470a4805438c372ff202ad7bf3f10165
Author: Mateusz Jończyk <mat.jonczyk@xxxxx>
Date: Wed Jul 6 22:01:44 2022 +0200
drm/radeon: avoid bogus "vram limit (0) must be a power of 2" warning
[ Upstream commit 9da2902609f7519c48eda84f953f72fee53f2b71 ]
I was getting the following message on boot on Linux 5.19-rc5:
radeon 0000:01:05.0: vram limit (0) must be a power of 2
(I didn't use any radeon.vramlimit commandline parameter).
This is caused by
commit 8c2d34eb53b9 ("drm/radeon: use kernel is_power_of_2 rather than local version")
which removed radeon_check_pot_argument() and converted its users to
is_power_of_2(). The two functions differ in its handling of 0, which is
the default value of radeon_vram_limit: radeon_check_pot_argument()
"incorrectly" considered it a power of 2, while is_power_of_2() does not.
An appropriate conditional silences the warning message.
It is not necessary to add a similar test to other callers of
is_power_of_2() in radeon_device.c. The matching commit in amdgpu:
commit 761175078466 ("drm/amdgpu: use kernel is_power_of_2 rather than local version")
is unaffected by this bug.
Tested on Radeon HD 3200.
Not ccing stable, this is not serious enough.
Fixes: 8c2d34eb53b9 ("drm/radeon: use kernel is_power_of_2 rather than local version")
Cc: Alex Deucher <alexander.deucher@xxxxxxx>
Cc: Christian König <christian.koenig@xxxxxxx>
Cc: "Pan, Xinhui" <Xinhui.Pan@xxxxxxx>
Cc: David Airlie <airlied@xxxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Cc: Jonathan Gray <jsg@xxxxxxxxx>
Signed-off-by: Mateusz Jończyk <mat.jonczyk@xxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
index 15692cb241fc..429644d5ddc6 100644
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -1113,7 +1113,7 @@ static int radeon_gart_size_auto(enum radeon_family family)
static void radeon_check_arguments(struct radeon_device *rdev)
{
/* vramlimit must be a power of two */
- if (!is_power_of_2(radeon_vram_limit)) {
+ if (radeon_vram_limit != 0 && !is_power_of_2(radeon_vram_limit)) {
dev_warn(rdev->dev, "vram limit (%d) must be a power of 2\n",
radeon_vram_limit);
radeon_vram_limit = 0;
