On 11/2/2021 12:33 PM, Christian König wrote:
Am 02.11.21 um 12:18 schrieb Lazar, Lijo:
On 11/2/2021 4:39 PM, Christian König wrote:
Am 02.11.21 um 11:11 schrieb Das, Nirmoy:
On 11/2/2021 9:00 AM, Lazar, Lijo wrote:
On 10/29/2021 8:39 PM, Nirmoy Das wrote:
We set WC memtype for aper_base but don't check return value
of arch_io_reserve_memtype_wc(). Be more defensive and return
early on error.
Signed-off-by: Nirmoy Das <nirmoy.das@xxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
index 073ba2af0b9c..6b25982a9077 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
@@ -1032,9 +1032,14 @@ int amdgpu_bo_init(struct amdgpu_device
*adev)
/* On A+A platform, VRAM can be mapped as WB */
if (!adev->gmc.xgmi.connected_to_cpu) {
/* reserve PAT memory space to WC for VRAM */
- arch_io_reserve_memtype_wc(adev->gmc.aper_base,
+ int r = arch_io_reserve_memtype_wc(adev->gmc.aper_base,
adev->gmc.aper_size);
BTW, isn't it more appropriate to use visible vram size? There are
cases where pci resize rounds aperture to the next higher size >
size of actual VRAM.
Good point, I will update this one and send again.
Not a good idea at all.
The aperture size is rounded up to the next power of two and that's
exactly what we should stick to if we don't want to get an error
code in return.
PCI rebar sizes have its restrictions. It jumps from 4G to 8G to 16G
and so on. Why we need to map 16G for a card with 12G VRAM? BTW, how
it increases the failure chance - this mapping happens in page sizes,
right?
Exactly that's the point. This mapping usually happens in power of two
in the same way as the PCI BAR sizes. So we should use 16GiB even for
a 12GiB card here.
Only some architectures work with page size mappings (e.g. x86 with
PAT enabled). Then we can indeed use the real VRAM size, but that is
absolutely not guaranteed as far as I know.
Thanks for clarifying this. I will push the patch with your suggested
changes.
Regards,
Nirmoy
Regards,
Christian.
Thanks,
Lijo
Regards,
Christian.
Regards,
Nirmoy
Thanks,
Lijo
+ if (r) {
+ DRM_ERROR("Unable to set WC memtype for the aperture
base\n");
+ return r;
+ }
+
/* Add an MTRR for the VRAM */
adev->gmc.vram_mtrr =
arch_phys_wc_add(adev->gmc.aper_base,
adev->gmc.aper_size);
