From: Mateusz Jończyk mat.jonczyk@o2.pl
[ 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@amd.com Cc: Christian König christian.koenig@amd.com Cc: "Pan, Xinhui" Xinhui.Pan@amd.com Cc: David Airlie airlied@linux.ie Cc: Daniel Vetter daniel@ffwll.ch Cc: Jonathan Gray jsg@jsg.id.au Signed-off-by: Mateusz Jończyk mat.jonczyk@o2.pl Signed-off-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/radeon/radeon_device.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
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;