All of the MediaTek SoCs supported by Panfrost can completely cut power
to the GPU during full system sleep without any user-noticeable delay
in the resume operation, as shown by measurements taken on multiple
MediaTek SoCs (MT8183/86/92/95).
As an example, for MT8195 - a "before" with only runtime PM operations
(so, without turning on/off regulators), and an "after" executing both
the system sleep .resume() handler and .runtime_resume() (so the time
refers to T_Resume + T_Runtime_Resume):
Average Panfrost-only system sleep resume time, before: ~33500ns
Average Panfrost-only system sleep resume time, after: ~336200ns
Keep in mind that this additional ~308200 nanoseconds delay happens only
in resume from a full system suspend, and not in runtime PM operations,
hence it is acceptable.
Measurements were also taken on MT8186, showing a delay of ~312000 ns.
Testing of this happened on all of the aforementioned MediaTek SoCs, but:
MT8183 got tested only by KernelCI with <=10 suspend/resume cycles
MT8186, MT8192, MT8195 were tested manually with over 100 suspend/resume
cycles with GNOME DE (Mutter + Wayland).
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
---
drivers/gpu/drm/panfrost/panfrost_drv.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
index 82f3c5fe9c58..f63382d9ab04 100644
--- a/drivers/gpu/drm/panfrost/panfrost_drv.c
+++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
@@ -734,7 +734,7 @@ static const struct panfrost_compatible mediatek_mt8183_b_data = {
.supply_names = mediatek_mt8183_b_supplies,
.num_pm_domains = ARRAY_SIZE(mediatek_mt8183_pm_domains),
.pm_domain_names = mediatek_mt8183_pm_domains,
- .pm_features = BIT(GPU_PM_CLK_DIS),
+ .pm_features = BIT(GPU_PM_CLK_DIS) | BIT(GPU_PM_VREG_OFF),
};
static const char * const mediatek_mt8186_pm_domains[] = { "core0", "core1" };
@@ -743,7 +743,7 @@ static const struct panfrost_compatible mediatek_mt8186_data = {
.supply_names = mediatek_mt8183_b_supplies,
.num_pm_domains = ARRAY_SIZE(mediatek_mt8186_pm_domains),
.pm_domain_names = mediatek_mt8186_pm_domains,
- .pm_features = BIT(GPU_PM_CLK_DIS),
+ .pm_features = BIT(GPU_PM_CLK_DIS) | BIT(GPU_PM_VREG_OFF),
};
static const char * const mediatek_mt8192_supplies[] = { "mali", NULL };
@@ -754,7 +754,7 @@ static const struct panfrost_compatible mediatek_mt8192_data = {
.supply_names = mediatek_mt8192_supplies,
.num_pm_domains = ARRAY_SIZE(mediatek_mt8192_pm_domains),
.pm_domain_names = mediatek_mt8192_pm_domains,
- .pm_features = BIT(GPU_PM_CLK_DIS),
+ .pm_features = BIT(GPU_PM_CLK_DIS) | BIT(GPU_PM_VREG_OFF),
};
static const struct of_device_id dt_match[] = {
--
2.42.0
