On 23/11/2024 23:59, Akhil P Oommen wrote:
On Tue, Nov 19, 2024 at 06:56:43PM +0100, Neil Armstrong wrote:
When requesting a DDR bandwidth level along a GPU frequency
level via the GMU, we can also specify the bus bandwidth usage in a 16bit
quantitized value.
For now simply request the maximum bus usage.
Why? You don't care about power efficiency?
Lets drop this patch. We don't care about AB vote yet.
I care about functionality, without this AB vote the spillall use
case that fails on SM8650 HDK fails on the SM8650 QRD.
AB is a quantitized value of the BW voted, so yes I expect we can have
100% of the BW voted, but since we scale the BW it's perfectly fine.
Neil
-Akhil
Signed-off-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
---
drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 11 +++++++++++
drivers/gpu/drm/msm/adreno/a6xx_hfi.h | 5 +++++
2 files changed, 16 insertions(+)
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
index dc2d0035544e7848e5c4ea27f1ea9a191f9c4991..36c0f67fd8e109aabf09a0804bacbed3593c39d7 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
@@ -134,6 +134,17 @@ void a6xx_gmu_set_freq(struct msm_gpu *gpu, struct dev_pm_opp *opp,
if (bw == gmu->gpu_bw_table[bw_index])
break;
}
+
+ if (bw_index) {
+ /*
+ * Append AB vote to the maximum bus usage.
+ * AB represents a quantitized 16bit value of the
+ * max ddr bandwidth we could use, let's simply
+ * request the maximum for now.
+ */
+ bw_index |= AB_VOTE(MAX_AB_VOTE);
+ bw_index |= AB_VOTE_ENABLE;
+ }
}
gmu->current_perf_index = perf_index;
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_hfi.h b/drivers/gpu/drm/msm/adreno/a6xx_hfi.h
index 528110169398f69f16443a29a1594d19c36fb595..52ba4a07d7b9a709289acd244a751ace9bdaab5d 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_hfi.h
+++ b/drivers/gpu/drm/msm/adreno/a6xx_hfi.h
@@ -173,6 +173,11 @@ struct a6xx_hfi_gx_bw_perf_vote_cmd {
u32 bw;
};
+#define AB_VOTE_MASK GENMASK(31, 16)
+#define MAX_AB_VOTE (FIELD_MAX(AB_VOTE_MASK) - 1)
+#define AB_VOTE(vote) FIELD_PREP(AB_VOTE_MASK, (vote))
+#define AB_VOTE_ENABLE BIT(8)
+
#define HFI_H2F_MSG_PREPARE_SLUMBER 33
struct a6xx_hfi_prep_slumber_cmd {
--
2.34.1
