[PATCH 2/2] drm/msm/a6xx: Use CX AO Counter register for timestamp on a750 GPUs

From: Neil Armstrong

Date: Tue Sep 08 2026 - 10:26:04 EST


The a750 uses the CX AO Counters instead of the GMU_ALWAYS_ON_COUNTER
register on A6xx and other A7xx GPUs, use it when running a A750 GPU.

Signed-off-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
---
drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
index f9de9329dee3..081e79ea4652 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
@@ -23,9 +23,15 @@ static u64 a6xx_gmu_get_timestamp(struct msm_gpu *gpu)
u64 count_hi, count_lo, temp;

do {
- count_hi = gmu_read(&a6xx_gpu->gmu, REG_A6XX_GMU_ALWAYS_ON_COUNTER_H);
- count_lo = gmu_read(&a6xx_gpu->gmu, REG_A6XX_GMU_ALWAYS_ON_COUNTER_L);
- temp = gmu_read(&a6xx_gpu->gmu, REG_A6XX_GMU_ALWAYS_ON_COUNTER_H);
+ if (adreno_is_a750_family(adreno_gpu)) {
+ count_hi = gmu_read(&a6xx_gpu->gmu, REG_A7XX_GMU_CX_AO_COUNTER_H);
+ count_lo = gmu_read(&a6xx_gpu->gmu, REG_A7XX_GMU_CX_AO_COUNTER_L);
+ temp = gmu_read(&a6xx_gpu->gmu, REG_A7XX_GMU_CX_AO_COUNTER_H);
+ } else {
+ count_hi = gmu_read(&a6xx_gpu->gmu, REG_A6XX_GMU_ALWAYS_ON_COUNTER_H);
+ count_lo = gmu_read(&a6xx_gpu->gmu, REG_A6XX_GMU_ALWAYS_ON_COUNTER_L);
+ temp = gmu_read(&a6xx_gpu->gmu, REG_A6XX_GMU_ALWAYS_ON_COUNTER_H);
+ }
} while (unlikely(count_hi != temp));

return (count_hi << 32) | count_lo;

--
2.34.1