Re: [PATCH v10 3/4] drm/panfrost: devfreq: Disable devfreq when num_supplies > 1
On 13/01/2021 06:07, Nicolas Boichat wrote:
GPUs with more than a single regulator (e.g. G72 on MT8183) will
require platform-specific handling for devfreq, for 2 reasons:
1. The opp core (drivers/opp/core.c:_generic_set_opp_regulator)
does not support multiple regulators, so we'll need custom
handlers.
2. Generally, platforms with 2 regulators have platform-specific
constraints on how the voltages should be set (e.g.
minimum/maximum voltage difference between them), so we
should not just create generic handlers that simply
change the voltages without taking care of those constraints.
Disable devfreq for now on those GPUs.
Signed-off-by: Nicolas Boichat
Reviewed-by: Tomeu Vizoso
Thanks for the clarification in the commit message.
Reviewed-by: Steven Price
---
(no changes since v9)
Changes in v9:
- Explain why devfreq needs to be disabled for GPUs with >1
regulators.
Changes in v8:
- Use DRM_DEV_INFO instead of ERROR
Changes in v7:
- Fix GPU ID in commit message
Changes in v6:
- New change
drivers/gpu/drm/panfrost/panfrost_devfreq.c | 9 +
1 file changed, 9 insertions(+)
diff --git a/drivers/gpu/drm/panfrost/panfrost_devfreq.c
b/drivers/gpu/drm/panfrost/panfrost_devfreq.c
index f44d28fad085..812cfecdee3b 100644
--- a/drivers/gpu/drm/panfrost/panfrost_devfreq.c
+++ b/drivers/gpu/drm/panfrost/panfrost_devfreq.c
@@ -92,6 +92,15 @@ int panfrost_devfreq_init(struct panfrost_device *pfdev)
struct thermal_cooling_device *cooling;
struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
+ if (pfdev->comp->num_supplies > 1) {
+ /*
+* GPUs with more than 1 supply require platform-specific
handling:
+* continue without devfreq
+*/
+ DRM_DEV_INFO(dev, "More than 1 supply is not supported yet\n");
+ return 0;
+ }
+
opp_table = dev_pm_opp_set_regulators(dev, pfdev->comp->supply_names,
pfdev->comp->num_supplies);
if (IS_ERR(opp_table)) {
[PATCH v10 3/4] drm/panfrost: devfreq: Disable devfreq when num_supplies > 1
GPUs with more than a single regulator (e.g. G72 on MT8183) will
require platform-specific handling for devfreq, for 2 reasons:
1. The opp core (drivers/opp/core.c:_generic_set_opp_regulator)
does not support multiple regulators, so we'll need custom
handlers.
2. Generally, platforms with 2 regulators have platform-specific
constraints on how the voltages should be set (e.g.
minimum/maximum voltage difference between them), so we
should not just create generic handlers that simply
change the voltages without taking care of those constraints.
Disable devfreq for now on those GPUs.
Signed-off-by: Nicolas Boichat
Reviewed-by: Tomeu Vizoso
---
(no changes since v9)
Changes in v9:
- Explain why devfreq needs to be disabled for GPUs with >1
regulators.
Changes in v8:
- Use DRM_DEV_INFO instead of ERROR
Changes in v7:
- Fix GPU ID in commit message
Changes in v6:
- New change
drivers/gpu/drm/panfrost/panfrost_devfreq.c | 9 +
1 file changed, 9 insertions(+)
diff --git a/drivers/gpu/drm/panfrost/panfrost_devfreq.c
b/drivers/gpu/drm/panfrost/panfrost_devfreq.c
index f44d28fad085..812cfecdee3b 100644
--- a/drivers/gpu/drm/panfrost/panfrost_devfreq.c
+++ b/drivers/gpu/drm/panfrost/panfrost_devfreq.c
@@ -92,6 +92,15 @@ int panfrost_devfreq_init(struct panfrost_device *pfdev)
struct thermal_cooling_device *cooling;
struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
+ if (pfdev->comp->num_supplies > 1) {
+ /*
+* GPUs with more than 1 supply require platform-specific
handling:
+* continue without devfreq
+*/
+ DRM_DEV_INFO(dev, "More than 1 supply is not supported yet\n");
+ return 0;
+ }
+
opp_table = dev_pm_opp_set_regulators(dev, pfdev->comp->supply_names,
pfdev->comp->num_supplies);
if (IS_ERR(opp_table)) {
--
2.30.0.284.gd98b1dd5eaa7-goog
