Re: [PATCH 1/9] drm/amdgpu/gfx7: Make amdgpu_gfx_mqd_sw_init() usable on GFX7

["Timur Kristóf" <timur.kristof@gmail.com>]

On Tuesday, July 14, 2026 5:19:57 PM Central European Summer Time Tvrtko 
Ursulin wrote:
> On 14/07/2026 16:05, Alex Deucher wrote:
> > On Tue, Jul 14, 2026 at 10:59 AM Tvrtko Ursulin <tursulin@ursulin.net> 
wrote:
> >> On 13/07/2026 13:58, Timur Kristóf wrote:
> >>> We don't use KIQ on GFX7 but otherwise MQD works the
> >>> same way as GFX8 and newer.
> >>> 
> >>> Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
> >>> ---
> >>> 
> >>>    drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c | 2 +-
> >>>    1 file changed, 1 insertion(+), 1 deletion(-)
> >>> 
> >>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
> >>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c index
> >>> 96c9d4f00b27..0f142c156afa 100644
> >>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
> >>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
> >>> @@ -420,7 +420,7 @@ int amdgpu_gfx_mqd_sw_init(struct amdgpu_device
> >>> *adev,
> >>> 
> >>>    #endif
> >>>    
> >>>        /* create MQD for KIQ */
> >>> 
> >>> -     if (!adev->enable_mes_kiq && !ring->mqd_obj) {
> >>> +     if (adev->asic_type >= CHIP_TOPAZ && !adev->enable_mes_kiq &&
> >>> !ring->mqd_obj) {>> 
> >> CHIP_TOPAZ is gfx7? Hm if it is then the branch would already run there.
> >> So the change is limiting the branch to a subset of platforms, while the
> >> patch title made me think it is enabling something on gfx7. Perhaps
> >> somehow indirectly or what am I not understanding?
> > 
> > TOPAZ is gfx8.

We currently don't use KIQ on GFX7 so the patch changes the code to allocate 
the BO only on GFX8 and newer. Topaz is the first GFX8 chip in the enum, so 
that's why the code checks >= TOPAZ here.

> Ah now I get it, thank you! Could maybe adev->gfx[0].kiq.something or be
> used to make it a bit self-documenting?

Technically, GFX7 supports the KIQ, amdgpu just doesn't use it. So, I fear 
that adding a field would mislead the reader into thinking that the HW support 
is missing when it really is just the kernel doesn't use it.

How would you feel about just updating the comment above the changed line?
Maybe like this?

/* create MQD for KIQ - only on GFX8+ GPUs where we use the KIQ */

I think that would make it self-explanatory.

> 
> >>>                /* originaly the KIQ MQD is put in GTT domain, but for
> >>>                SRIOV VRAM domain is a must>>>                
> >>>                 * otherwise hypervisor trigger SAVE_VF fail after driver
> >>>                 unloaded which mean MQD * deallocated and gart_unbind,
> >>>                 to strict diverage we decide to use VRAM domain for