On 20/04/2023 00:26, Konrad Dybcio wrote:
On 19.04.2023 22:11, Jeykumar Sankaran wrote:
On 4/19/2023 12:48 PM, Konrad Dybcio wrote:
On 19.04.2023 21:06, Jeykumar Sankaran wrote:
On 4/17/2023 8:30 AM, Konrad Dybcio wrote:
Apart from the already handled data bus (MAS_MDP_Pn<->DDR), there's
another path that needs to be handled to ensure MDSS functions properly,
namely the "reg bus", a.k.a the CPU-MDSS interconnect.
Gating that path may have a variety of effects.. from none to otherwise
inexplicable DSI timeouts..
On the DPU side, we need to keep the bus alive. The vendor driver
kickstarts it to max (300Mbps) throughput on first commit, but in
exchange for some battery life in rare DPU-enabled-panel-disabled
usecases, we can request it at DPU init and gate it at suspend.
Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx>
---
drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 22 ++++++++++++++++++++--
drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h | 1 +
2 files changed, 21 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
index dd6c1c40ab9e..d1f77faebbc0 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
@@ -384,15 +384,17 @@ static int dpu_kms_global_obj_init(struct dpu_kms *dpu_kms)
return 0;
}
-static int dpu_kms_parse_data_bus_icc_path(struct dpu_kms *dpu_kms)
+static int dpu_kms_parse_icc_paths(struct dpu_kms *dpu_kms)
{
struct icc_path *path0;
struct icc_path *path1;
+ struct icc_path *reg_bus_path;
struct drm_device *dev = dpu_kms->dev;
struct device *dpu_dev = dev->dev;
path0 = msm_icc_get(dpu_dev, "mdp0-mem");
path1 = msm_icc_get(dpu_dev, "mdp1-mem");
+ reg_bus_path = msm_icc_get(dpu_dev, "cpu-cfg");
if (IS_ERR_OR_NULL(path0))
return PTR_ERR_OR_ZERO(path0);
@@ -404,6 +406,10 @@ static int dpu_kms_parse_data_bus_icc_path(struct dpu_kms *dpu_kms)
dpu_kms->mdp_path[1] = path1;
dpu_kms->num_mdp_paths++;
}
+
+ if (!IS_ERR_OR_NULL(reg_bus_path))
+ dpu_kms->reg_bus_path = reg_bus_path;
+
return 0;
}
@@ -1039,7 +1045,7 @@ static int dpu_kms_hw_init(struct msm_kms *kms)
DPU_DEBUG("REG_DMA is not defined");
}
- dpu_kms_parse_data_bus_icc_path(dpu_kms);
+ dpu_kms_parse_icc_paths(dpu_kms);
rc = pm_runtime_resume_and_get(&dpu_kms->pdev->dev);
if (rc < 0)
@@ -1241,6 +1247,9 @@ static int __maybe_unused dpu_runtime_suspend(struct device *dev)
for (i = 0; i < dpu_kms->num_mdp_paths; i++)
icc_set_bw(dpu_kms->mdp_path[i], 0, 0);
+ if (dpu_kms->reg_bus_path)
+ icc_set_bw(dpu_kms->reg_bus_path, 0, 0);
+
return 0;
}
@@ -1261,6 +1270,15 @@ static int __maybe_unused dpu_runtime_resume(struct device *dev)
return rc;
}
+ /*
+ * The vendor driver supports setting 76.8 / 150 / 300 Mbps on this
How do you arrive at these distint BW values? Are they provided by the ICC fwk for the given path?
They're hardcoded in the SDE driver.
Konrad
These bandwidths are derived from the scaling frequencies of all the buses participating in the icc-path. So they cannot be constants. Ideally they should be read from the hw catalog data of the respective platform.
msm-5.4 : rotator/sde_rotator_base.c
static const struct sde_rot_bus_data sde_rot_reg_bus_table[] = {
{0, 0},
{0, 76800},
{0, 150000},
{0, 300000},
};
One of the two voters begs to disagree, but I do indeed see that some
SoCs (lahaina, yupik, shima..) cast votes for 74/148/265 MBps instead
of 77/150/300 from the MDSS device (with rotator being considered
separate), or so say their DTs, thanks for pointing that out.
I wonder if it makes the difference. The values are pretty close.
Anyway, we now have the driver data, so you can push these values to the
data.
Nonetheless, this code would taste good with bolognese sauce..
Konrad
Jeykumar S.
+ * path, but it seems to go for the highest level when display output
+ * is enabled and zero otherwise. For simplicity, we can assume that
+ * DPU being enabled and running implies that.
+ */
+ if (dpu_kms->reg_bus_path)
+ icc_set_bw(dpu_kms->reg_bus_path, 0, MBps_to_icc(300));
+
dpu_vbif_init_memtypes(dpu_kms);
drm_for_each_encoder(encoder, ddev)
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
index d5d9bec90705..c332381d58c4 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
@@ -111,6 +111,7 @@ struct dpu_kms {
atomic_t bandwidth_ref;
struct icc_path *mdp_path[2];
u32 num_mdp_paths;
+ struct icc_path *reg_bus_path;
};
struct vsync_info {
--
With best wishes
Dmitry
