Re: [PATCH] drm/xe/debugfs: Don't expose dgfx residencies attributes on VF

[Gustavo Sousa <gustavo.sousa@intel.com>]

Quoting Michal Wajdeczko (2025-09-05 14:36:25-03:00)
>In addition of checking if we are running on the BATTLEMAGE,
>we should also check for not being a VF driver, as VFs can't
>access necessary registers, and doing so leads to:
>
> | .. [drm] GT0: VF is trying to read an inaccessible register 0x35b004+0x0
> | RIP: 0010:xe_gt_sriov_vf_read32+0x5e2/0x8a0 [xe]
> | Call Trace:
> |  xe_mmio_read32+0x110/0x280 [xe]
> |  read_residency_counter+0x42/0xd0 [xe]
> |  dgfx_pkg_residencies_show+0x115/0x190 [xe]
> | .. [drm] Package G2 counter failed to read, ret -19
>
>or
>
> | .. [drm] GT0: VF is trying to read an inaccessible register 0x35b004+0x0
> | RIP: 0010:xe_gt_sriov_vf_read32+0x5e2/0x8a0 [xe]
> | Call Trace:
> |  xe_mmio_read32+0x110/0x280 [xe]
> |  read_residency_counter+0x42/0xd0 [xe]
> |  dgfx_pcie_link_residencies_show+0xe7/0x160 [xe]
> | .. [drm] PCIE LINK L0 RESIDENCY counter failed to read, ret -19
>
>Similarly, there is no point to expose inject_csc_hw_error on VFs,
>as HW errors support is already disabled for VFs.
>
>Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
>Cc: Soham Purkait <soham.purkait@intel.com>
>Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
>Cc: Riana Tauro <riana.tauro@intel.com>

I posted a very similar patch[1] ~1 month ago.

There was a spec-related question from Rodrigo, for which I could not
find the answer.

[1] https://lore.kernel.org/all/20250729-skip-residency-debugfs-for-vfs-v1-1-3c5edec08c8b@intel.com/

--
Gustavo Sousa

>---
> drivers/gpu/drm/xe/xe_debugfs.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/drivers/gpu/drm/xe/xe_debugfs.c b/drivers/gpu/drm/xe/xe_debugfs.c
>index 4b71570529a6..8be8304cb05c 100644
>--- a/drivers/gpu/drm/xe/xe_debugfs.c
>+++ b/drivers/gpu/drm/xe/xe_debugfs.c
>@@ -346,7 +346,7 @@ void xe_debugfs_register(struct xe_device *xe)
>                                  ARRAY_SIZE(debugfs_list),
>                                  root, minor);
> 
>-        if (xe->info.platform == XE_BATTLEMAGE) {
>+        if (xe->info.platform == XE_BATTLEMAGE && !IS_SRIOV_VF(xe)) {
>                 drm_debugfs_create_files(debugfs_residencies,
>                                          ARRAY_SIZE(debugfs_residencies),
>                                          root, minor);
>-- 
>2.47.1
>