On 7/22/2025 9:08 PM, Rob Clark wrote: > On Tue, Jul 22, 2025 at 6:50 AM Dmitry Baryshkov > <dmitry.barysh...@oss.qualcomm.com> wrote: >> >> On Sun, Jul 20, 2025 at 05:46:13PM +0530, Akhil P Oommen wrote: >>> When IFPC is supported, devfreq idling is redundant and adds >>> unnecessary pm suspend/wake latency. So skip it when IFPC is >>> supported. >> >> With this in place we have a dummy devfreq instance which does nothing. >> Wouldn't it be better to skip registering devfreq if IFPC is supported >> on the platform? > > devfreq is still scaling the freq. What is being bypassed is > essentially a CPU based version of IFPC (because on sc7180 we didn't > have IFPC > > Currently only a618 and 7c3 enable gpu_clamp_to_idle.. if at some > point those grew IFPC support we could remove the trickery to drop GPU > to min freq when it is idle altogether.
There are 2 functionalities here: 1. Clamp-to-idle: enabled only on a618/7c3 2. boost-after-idle: Enabled for all GPUs. With this patch, we are skipping both when IFPC is supported. In the absence of latency due to clamp-to-idle, do you think a618 (relatively weaker GPU) would require boost-after-idle to keep with the UI/composition workload for its typical configuration (1080p@60hz)? If yes, I should probably create a quirk to disable boost-after-idle for premium tier GPUs, instead of tying it to IFPC feature. -Akhil. > > BR, > -R > >>> >>> Signed-off-by: Akhil P Oommen <akhi...@oss.qualcomm.com> >>> --- >>> drivers/gpu/drm/msm/msm_gpu_devfreq.c | 6 ++++++ >>> 1 file changed, 6 insertions(+) >>> >>> diff --git a/drivers/gpu/drm/msm/msm_gpu_devfreq.c >>> b/drivers/gpu/drm/msm/msm_gpu_devfreq.c >>> index >>> 2e1d5c3432728cde15d91f69da22bb915588fe86..53ef2add5047e7d6b6371af949cab36ce8409372 >>> 100644 >>> --- a/drivers/gpu/drm/msm/msm_gpu_devfreq.c >>> +++ b/drivers/gpu/drm/msm/msm_gpu_devfreq.c >>> @@ -4,6 +4,7 @@ >>> * Author: Rob Clark <robdcl...@gmail.com> >>> */ >>> >>> +#include "adreno/adreno_gpu.h" >>> #include "msm_gpu.h" >>> #include "msm_gpu_trace.h" >>> >>> @@ -300,6 +301,8 @@ void msm_devfreq_active(struct msm_gpu *gpu) >>> if (!has_devfreq(gpu)) >>> return; >>> >>> + if (to_adreno_gpu(gpu)->info->quirks & ADRENO_QUIRK_IFPC) >>> + return; >>> /* >>> * Cancel any pending transition to idle frequency: >>> */ >>> @@ -370,6 +373,9 @@ void msm_devfreq_idle(struct msm_gpu *gpu) >>> if (!has_devfreq(gpu)) >>> return; >>> >>> + if (to_adreno_gpu(gpu)->info->quirks & ADRENO_QUIRK_IFPC) >>> + return; >>> + >>> msm_hrtimer_queue_work(&df->idle_work, ms_to_ktime(1), >>> HRTIMER_MODE_REL); >>> } >>> >>> -- >>> 2.50.1 >>> >> >> -- >> With best wishes >> Dmitry
