2020-10-29 09:08:25

by Akhil P Oommen

[permalink] [raw]
Subject: [PATCH v4 1/3] drm/msm: Add support for GPU cooling

Register GPU as a devfreq cooling device so that it can be passively
cooled by the thermal framework.

Signed-off-by: Akhil P Oommen <[email protected]>
Reviewed-by: Matthias Kaehlcke <[email protected]>
---
Changes in v4:
1. Fix gpu cooling map.
2. Add mka's Reviewed-by tag.
Changes in v3:
1. Minor fix in binding documentation (RobH)
Changes in v2:
1. Update the dt bindings documentation

drivers/gpu/drm/msm/msm_gpu.c | 12 ++++++++++++
drivers/gpu/drm/msm/msm_gpu.h | 2 ++
2 files changed, 14 insertions(+)

diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
index 55d1648..9f9db46 100644
--- a/drivers/gpu/drm/msm/msm_gpu.c
+++ b/drivers/gpu/drm/msm/msm_gpu.c
@@ -14,6 +14,7 @@
#include <generated/utsrelease.h>
#include <linux/string_helpers.h>
#include <linux/devfreq.h>
+#include <linux/devfreq_cooling.h>
#include <linux/devcoredump.h>
#include <linux/sched/task.h>

@@ -107,9 +108,18 @@ static void msm_devfreq_init(struct msm_gpu *gpu)
if (IS_ERR(gpu->devfreq.devfreq)) {
DRM_DEV_ERROR(&gpu->pdev->dev, "Couldn't initialize GPU devfreq\n");
gpu->devfreq.devfreq = NULL;
+ return;
}

devfreq_suspend_device(gpu->devfreq.devfreq);
+
+ gpu->cooling = of_devfreq_cooling_register(gpu->pdev->dev.of_node,
+ gpu->devfreq.devfreq);
+ if (IS_ERR(gpu->cooling)) {
+ DRM_DEV_ERROR(&gpu->pdev->dev,
+ "Couldn't register GPU cooling device\n");
+ gpu->cooling = NULL;
+ }
}

static int enable_pwrrail(struct msm_gpu *gpu)
@@ -1005,4 +1015,6 @@ void msm_gpu_cleanup(struct msm_gpu *gpu)
gpu->aspace->mmu->funcs->detach(gpu->aspace->mmu);
msm_gem_address_space_put(gpu->aspace);
}
+
+ devfreq_cooling_unregister(gpu->cooling);
}
diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h
index 6c9e1fd..9a8f20d 100644
--- a/drivers/gpu/drm/msm/msm_gpu.h
+++ b/drivers/gpu/drm/msm/msm_gpu.h
@@ -147,6 +147,8 @@ struct msm_gpu {
struct msm_gpu_state *crashstate;
/* True if the hardware supports expanded apriv (a650 and newer) */
bool hw_apriv;
+
+ struct thermal_cooling_device *cooling;
};

static inline struct msm_gpu *dev_to_gpu(struct device *dev)
--
2.7.4


2020-10-29 20:52:31

by Matthias Kaehlcke

[permalink] [raw]
Subject: Re: [v4,1/3] drm/msm: Add support for GPU cooling

On Thu, Oct 29, 2020 at 01:37:19PM +0530, Akhil P Oommen wrote:
> Register GPU as a devfreq cooling device so that it can be passively
> cooled by the thermal framework.
>
> Signed-off-by: Akhil P Oommen <[email protected]>
> Reviewed-by: Matthias Kaehlcke <[email protected]>

Wait, I did not post a 'Reviewed-by' tag for this patch!

I think the patch should be ok, but I'm still not super happy
about the resource management involving devfreq in general (see
discussion on https://patchwork.freedesktop.org/patch/394291/?series=82476&rev=1).
It's not really something introduced by this patch, but if it ever
gets fixed releasing the cooling device at the end of
msm_gpu_cleanup() after everything else might cause trouble.

In summary, I'm supportive of landing this patch, but reluctant to
'sign it off' because of the above.

In any case:

Tested-by: Matthias Kaehlcke <[email protected]>

2020-10-30 05:09:40

by Akhil P Oommen

[permalink] [raw]
Subject: Re: [v4,1/3] drm/msm: Add support for GPU cooling

On 10/30/2020 2:18 AM, [email protected] wrote:
> On Thu, Oct 29, 2020 at 01:37:19PM +0530, Akhil P Oommen wrote:
>> Register GPU as a devfreq cooling device so that it can be passively
>> cooled by the thermal framework.
>>
>> Signed-off-by: Akhil P Oommen <[email protected]>
>> Reviewed-by: Matthias Kaehlcke <[email protected]>
>
> Wait, I did not post a 'Reviewed-by' tag for this patch!
>
> I think the patch should be ok, but I'm still not super happy
> about the resource management involving devfreq in general (see
> discussion on https://patchwork.freedesktop.org/patch/394291/?series=82476&rev=1).
> It's not really something introduced by this patch, but if it ever
> gets fixed releasing the cooling device at the end of
> msm_gpu_cleanup() after everything else might cause trouble.
>
> In summary, I'm supportive of landing this patch, but reluctant to
> 'sign it off' because of the above.
>
> In any case:
>
> Tested-by: Matthias Kaehlcke <[email protected]>
Sorry, Matthias. My mistake. You shared the reviewed tag for the
dt-bindings update. Will fix this ASAP. Thanks for verifying this.

-Akhil.
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