FAILED: patch "[PATCH] drm/msm/a6xx: Fix PDC sleep sequence" failed to apply to 6.6-stable tree

FAILED: patch "[PATCH] drm/msm/a6xx: Fix PDC sleep sequence" failed to apply to 6.6-stable tree

[gregkh]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x f248d5d5159a88ded55329f0b1b463d0f4094228
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025101631-punctual-jaybird-dba5@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From f248d5d5159a88ded55329f0b1b463d0f4094228 Mon Sep 17 00:00:00 2001
From: Akhil P Oommen <akhilpo@oss.qualcomm.com>
Date: Mon, 8 Sep 2025 13:56:57 +0530
Subject: [PATCH] drm/msm/a6xx: Fix PDC sleep sequence

Since the PDC resides out of the GPU subsystem and cannot be reset in
case it enters bad state, utmost care must be taken to trigger the PDC
wake/sleep routines in the correct order.

The PDC wake sequence can be exercised only after a PDC sleep sequence.
Additionally, GMU firmware should initialize a few registers before the
KMD can trigger a PDC sleep sequence. So PDC sleep can't be done if the
GMU firmware has not initialized. Track these dependencies using a new
status variable and trigger PDC sleep/wake sequences appropriately.

Cc: stable@vger.kernel.org
Fixes: 4b565ca5a2cb ("drm/msm: Add A6XX device support")
Signed-off-by: Akhil P Oommen <akhilpo@oss.qualcomm.com>
Patchwork: https://patchwork.freedesktop.org/patch/673362/
Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
index e74651d5bd7a..5594499ad2d1 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
@@ -279,6 +279,8 @@ static int a6xx_gmu_start(struct a6xx_gmu *gmu)
 	if (ret)
 		DRM_DEV_ERROR(gmu->dev, "GMU firmware initialization timed out\n");
 
+	set_bit(GMU_STATUS_FW_START, &gmu->status);
+
 	return ret;
 }
 
@@ -525,6 +527,9 @@ static int a6xx_rpmh_start(struct a6xx_gmu *gmu)
 	int ret;
 	u32 val;
 
+	if (!test_and_clear_bit(GMU_STATUS_PDC_SLEEP, &gmu->status))
+		return 0;
+
 	gmu_write(gmu, REG_A6XX_GMU_RSCC_CONTROL_REQ, BIT(1));
 
 	ret = gmu_poll_timeout(gmu, REG_A6XX_GMU_RSCC_CONTROL_ACK, val,
@@ -552,6 +557,9 @@ static void a6xx_rpmh_stop(struct a6xx_gmu *gmu)
 	int ret;
 	u32 val;
 
+	if (test_and_clear_bit(GMU_STATUS_FW_START, &gmu->status))
+		return;
+
 	gmu_write(gmu, REG_A6XX_GMU_RSCC_CONTROL_REQ, 1);
 
 	ret = gmu_poll_timeout_rscc(gmu, REG_A6XX_GPU_RSCC_RSC_STATUS0_DRV0,
@@ -560,6 +568,8 @@ static void a6xx_rpmh_stop(struct a6xx_gmu *gmu)
 		DRM_DEV_ERROR(gmu->dev, "Unable to power off the GPU RSC\n");
 
 	gmu_write(gmu, REG_A6XX_GMU_RSCC_CONTROL_REQ, 0);
+
+	set_bit(GMU_STATUS_PDC_SLEEP, &gmu->status);
 }
 
 static inline void pdc_write(void __iomem *ptr, u32 offset, u32 value)
@@ -688,8 +698,6 @@ static void a6xx_gmu_rpmh_init(struct a6xx_gmu *gmu)
 	/* ensure no writes happen before the uCode is fully written */
 	wmb();
 
-	a6xx_rpmh_stop(gmu);
-
 err:
 	if (!IS_ERR_OR_NULL(pdcptr))
 		iounmap(pdcptr);
@@ -849,19 +857,15 @@ static int a6xx_gmu_fw_start(struct a6xx_gmu *gmu, unsigned int state)
 	else
 		gmu_write(gmu, REG_A6XX_GMU_GENERAL_7, 1);
 
-	if (state == GMU_WARM_BOOT) {
-		ret = a6xx_rpmh_start(gmu);
-		if (ret)
-			return ret;
-	} else {
+	ret = a6xx_rpmh_start(gmu);
+	if (ret)
+		return ret;
+
+	if (state == GMU_COLD_BOOT) {
 		if (WARN(!adreno_gpu->fw[ADRENO_FW_GMU],
 			"GMU firmware is not loaded\n"))
 			return -ENOENT;
 
-		ret = a6xx_rpmh_start(gmu);
-		if (ret)
-			return ret;
-
 		ret = a6xx_gmu_fw_load(gmu);
 		if (ret)
 			return ret;
@@ -1046,6 +1050,8 @@ static void a6xx_gmu_force_off(struct a6xx_gmu *gmu)
 
 	/* Reset GPU core blocks */
 	a6xx_gpu_sw_reset(gpu, true);
+
+	a6xx_rpmh_stop(gmu);
 }
 
 static void a6xx_gmu_set_initial_freq(struct msm_gpu *gpu, struct a6xx_gmu *gmu)
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.h b/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
index d1ce11131ba6..069a8c9474e8 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
@@ -117,6 +117,12 @@ struct a6xx_gmu {
 
 	struct qmp *qmp;
 	struct a6xx_hfi_msg_bw_table *bw_table;
+
+/* To check if we can trigger sleep seq at PDC. Cleared in a6xx_rpmh_stop() */
+#define GMU_STATUS_FW_START	0
+/* To track if PDC sleep seq was done */
+#define GMU_STATUS_PDC_SLEEP	1
+	unsigned long status;
 };
 
 static inline u32 gmu_read(struct a6xx_gmu *gmu, u32 offset)

[PATCH 6.6.y 1/2] drm/msm/adreno: De-spaghettify the use of memory barriers

[Sasha Levin]

From: Konrad Dybcio <konrad.dybcio@linaro.org>

[ Upstream commit 43ec1a202cfa9f765412d325b93873284e7c3d82 ]

Memory barriers help ensure instruction ordering, NOT time and order
of actual write arrival at other observers (e.g. memory-mapped IP).
On architectures employing weak memory ordering, the latter can be a
giant pain point, and it has been as part of this driver.

Moreover, the gpu_/gmu_ accessors already use non-relaxed versions of
readl/writel, which include r/w (respectively) barriers.

Replace the barriers with a readback (or drop altogether where possible)
that ensures the previous writes have exited the write buffer (as the CPU
must flush the write to the register it's trying to read back).

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/600869/
Reviewed-by: Akhil P Oommen <quic_akhilpo@quicinc.com>
Signed-off-by: Rob Clark <robdclark@chromium.org>
Stable-dep-of: f248d5d5159a ("drm/msm/a6xx: Fix PDC sleep sequence")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/msm/adreno/a6xx_gmu.c |  4 +---
 drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 10 ++++++----
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
index e7136b7759cb3..0a30ecc81a8cc 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
@@ -460,9 +460,7 @@ static int a6xx_rpmh_start(struct a6xx_gmu *gmu)
 	int ret;
 	u32 val;
 
-	gmu_write(gmu, REG_A6XX_GMU_RSCC_CONTROL_REQ, 1 << 1);
-	/* Wait for the register to finish posting */
-	wmb();
+	gmu_write(gmu, REG_A6XX_GMU_RSCC_CONTROL_REQ, BIT(1));
 
 	ret = gmu_poll_timeout(gmu, REG_A6XX_GMU_RSCC_CONTROL_ACK, val,
 		val & (1 << 1), 100, 10000);
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
index 3664c1476a83a..00bfc6f38f459 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
@@ -1209,14 +1209,16 @@ static int hw_init(struct msm_gpu *gpu)
 	/* Clear GBIF halt in case GX domain was not collapsed */
 	if (adreno_is_a619_holi(adreno_gpu)) {
 		gpu_write(gpu, REG_A6XX_GBIF_HALT, 0);
+		gpu_read(gpu, REG_A6XX_GBIF_HALT);
+
 		gpu_write(gpu, REG_A6XX_RBBM_GPR0_CNTL, 0);
-		/* Let's make extra sure that the GPU can access the memory.. */
-		mb();
+		gpu_read(gpu, REG_A6XX_RBBM_GPR0_CNTL);
 	} else if (a6xx_has_gbif(adreno_gpu)) {
 		gpu_write(gpu, REG_A6XX_GBIF_HALT, 0);
+		gpu_read(gpu, REG_A6XX_GBIF_HALT);
+
 		gpu_write(gpu, REG_A6XX_RBBM_GBIF_HALT, 0);
-		/* Let's make extra sure that the GPU can access the memory.. */
-		mb();
+		gpu_read(gpu, REG_A6XX_RBBM_GBIF_HALT);
 	}
 
 	gpu_write(gpu, REG_A6XX_RBBM_SECVID_TSB_CNTL, 0);
-- 
2.51.0

[PATCH 6.6.y 2/2] drm/msm/a6xx: Fix PDC sleep sequence

[Sasha Levin]

From: Akhil P Oommen <akhilpo@oss.qualcomm.com>

[ Upstream commit f248d5d5159a88ded55329f0b1b463d0f4094228 ]

Since the PDC resides out of the GPU subsystem and cannot be reset in
case it enters bad state, utmost care must be taken to trigger the PDC
wake/sleep routines in the correct order.

The PDC wake sequence can be exercised only after a PDC sleep sequence.
Additionally, GMU firmware should initialize a few registers before the
KMD can trigger a PDC sleep sequence. So PDC sleep can't be done if the
GMU firmware has not initialized. Track these dependencies using a new
status variable and trigger PDC sleep/wake sequences appropriately.

Cc: stable@vger.kernel.org
Fixes: 4b565ca5a2cb ("drm/msm: Add A6XX device support")
Signed-off-by: Akhil P Oommen <akhilpo@oss.qualcomm.com>
Patchwork: https://patchwork.freedesktop.org/patch/673362/
Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>
[ omitted A7XX GPU logic and newer struct fields ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 34 ++++++++++++++++-----------
 drivers/gpu/drm/msm/adreno/a6xx_gmu.h |  6 +++++
 2 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
index 0a30ecc81a8cc..c50aafa0ecdb6 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
@@ -230,6 +230,8 @@ static int a6xx_gmu_start(struct a6xx_gmu *gmu)
 	if (ret)
 		DRM_DEV_ERROR(gmu->dev, "GMU firmware initialization timed out\n");
 
+	set_bit(GMU_STATUS_FW_START, &gmu->status);
+
 	return ret;
 }
 
@@ -460,6 +462,9 @@ static int a6xx_rpmh_start(struct a6xx_gmu *gmu)
 	int ret;
 	u32 val;
 
+	if (!test_and_clear_bit(GMU_STATUS_PDC_SLEEP, &gmu->status))
+		return 0;
+
 	gmu_write(gmu, REG_A6XX_GMU_RSCC_CONTROL_REQ, BIT(1));
 
 	ret = gmu_poll_timeout(gmu, REG_A6XX_GMU_RSCC_CONTROL_ACK, val,
@@ -487,6 +492,9 @@ static void a6xx_rpmh_stop(struct a6xx_gmu *gmu)
 	int ret;
 	u32 val;
 
+	if (test_and_clear_bit(GMU_STATUS_FW_START, &gmu->status))
+		return;
+
 	gmu_write(gmu, REG_A6XX_GMU_RSCC_CONTROL_REQ, 1);
 
 	ret = gmu_poll_timeout_rscc(gmu, REG_A6XX_GPU_RSCC_RSC_STATUS0_DRV0,
@@ -495,6 +503,8 @@ static void a6xx_rpmh_stop(struct a6xx_gmu *gmu)
 		DRM_DEV_ERROR(gmu->dev, "Unable to power off the GPU RSC\n");
 
 	gmu_write(gmu, REG_A6XX_GMU_RSCC_CONTROL_REQ, 0);
+
+	set_bit(GMU_STATUS_PDC_SLEEP, &gmu->status);
 }
 
 static inline void pdc_write(void __iomem *ptr, u32 offset, u32 value)
@@ -615,8 +625,6 @@ static void a6xx_gmu_rpmh_init(struct a6xx_gmu *gmu)
 	/* ensure no writes happen before the uCode is fully written */
 	wmb();
 
-	a6xx_rpmh_stop(gmu);
-
 err:
 	if (!IS_ERR_OR_NULL(pdcptr))
 		iounmap(pdcptr);
@@ -753,22 +761,18 @@ static int a6xx_gmu_fw_start(struct a6xx_gmu *gmu, unsigned int state)
 		gmu_write(gmu, REG_A6XX_GPU_GMU_CX_GMU_CX_FAL_INTF, 1);
 	}
 
-	if (state == GMU_WARM_BOOT) {
-		ret = a6xx_rpmh_start(gmu);
-		if (ret)
-			return ret;
-	} else {
+	/* Turn on register retention */
+	gmu_write(gmu, REG_A6XX_GMU_GENERAL_7, 1);
+
+	ret = a6xx_rpmh_start(gmu);
+	if (ret)
+		return ret;
+
+	if (state == GMU_COLD_BOOT) {
 		if (WARN(!adreno_gpu->fw[ADRENO_FW_GMU],
 			"GMU firmware is not loaded\n"))
 			return -ENOENT;
 
-		/* Turn on register retention */
-		gmu_write(gmu, REG_A6XX_GMU_GENERAL_7, 1);
-
-		ret = a6xx_rpmh_start(gmu);
-		if (ret)
-			return ret;
-
 		ret = a6xx_gmu_fw_load(gmu);
 		if (ret)
 			return ret;
@@ -907,6 +911,8 @@ static void a6xx_gmu_force_off(struct a6xx_gmu *gmu)
 
 	/* Reset GPU core blocks */
 	a6xx_gpu_sw_reset(gpu, true);
+
+	a6xx_rpmh_stop(gmu);
 }
 
 static void a6xx_gmu_set_initial_freq(struct msm_gpu *gpu, struct a6xx_gmu *gmu)
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.h b/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
index 236f81a43caa6..6a28ecaf8594e 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
@@ -96,6 +96,12 @@ struct a6xx_gmu {
 	/* For power domain callback */
 	struct notifier_block pd_nb;
 	struct completion pd_gate;
+
+/* To check if we can trigger sleep seq at PDC. Cleared in a6xx_rpmh_stop() */
+#define GMU_STATUS_FW_START	0
+/* To track if PDC sleep seq was done */
+#define GMU_STATUS_PDC_SLEEP	1
+	unsigned long status;
 };
 
 static inline u32 gmu_read(struct a6xx_gmu *gmu, u32 offset)
-- 
2.51.0