[PATCH 1/3] drm/amdgpu: Do not program AGP BAR regs under SRIOV

[Deucher, Alexander]

[Public]

Are there any cases where the asic_type check would cause this register to fail to get programmed?

Alex

________________________________
From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> on behalf of Victor Lu <victorchengchi.lu at amd.com>
Sent: Thursday, February 13, 2025 7:13 PM
To: amd-gfx at lists.freedesktop.org <amd-gfx at lists.freedesktop.org>
Cc: Lu, Victor Cheng Chi (Victor) <VictorChengChi.Lu at amd.com>; hoarce.chen at amd.com <hoarce.chen at amd.com>
Subject: [PATCH 1/3] drm/amdgpu: Do not program AGP BAR regs under SRIOV

SRIOV VF does not have write access to AGP BAR regs.
Skip the writes to avoid a dmesg warning.

Signed-off-by: Victor Lu <victorchengchi.lu at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/gfxhub_v1_0.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/gfxhub_v1_0.c b/drivers/gpu/drm/amd/amdgpu/gfxhub_v1_0.c
index 0e3ddea7b8e0..a7bfc9f41d0e 100644
--- a/drivers/gpu/drm/amd/amdgpu/gfxhub_v1_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gfxhub_v1_0.c
@@ -92,12 +92,12 @@ static void gfxhub_v1_0_init_system_aperture_regs(struct amdgpu_device *adev)
 {
         uint64_t value;

-       /* Program the AGP BAR */
-       WREG32_SOC15_RLC(GC, 0, mmMC_VM_AGP_BASE, 0);
-       WREG32_SOC15_RLC(GC, 0, mmMC_VM_AGP_BOT, adev->gmc.agp_start >> 24);
-       WREG32_SOC15_RLC(GC, 0, mmMC_VM_AGP_TOP, adev->gmc.agp_end >> 24);
-
         if (!amdgpu_sriov_vf(adev) || adev->asic_type <= CHIP_VEGA10) {
+               /* Program the AGP BAR */
+               WREG32_SOC15_RLC(GC, 0, mmMC_VM_AGP_BASE, 0);
+               WREG32_SOC15_RLC(GC, 0, mmMC_VM_AGP_BOT, adev->gmc.agp_start >> 24);
+               WREG32_SOC15_RLC(GC, 0, mmMC_VM_AGP_TOP, adev->gmc.agp_end >> 24);
+
                 /* Program the system aperture low logical page number. */
                 WREG32_SOC15_RLC(GC, 0, mmMC_VM_SYSTEM_APERTURE_LOW_ADDR,
                         min(adev->gmc.fb_start, adev->gmc.agp_start) >> 18);
--
2.34.1

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