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charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 12, 2020 at 07:03:51PM +0530, Akhil P Oommen wrote: > On 10/10/2020 12:06 AM, mka@chromium.org wrote: > > Hi Akhil, > > > > On Thu, Oct 08, 2020 at 10:39:07PM +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 > > > --- > > > drivers/gpu/drm/msm/msm_gpu.c | 13 ++++++++++++- > > > drivers/gpu/drm/msm/msm_gpu.h | 2 ++ > > > 2 files changed, 14 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c > > > index 55d1648..93ffd66 100644 > > > --- a/drivers/gpu/drm/msm/msm_gpu.c > > > +++ b/drivers/gpu/drm/msm/msm_gpu.c > > > @@ -14,6 +14,7 @@ > > > #include > > > #include > > > #include > > > +#include > > > #include > > > #include > > > @@ -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) > > > @@ -926,7 +936,6 @@ int msm_gpu_init(struct drm_device *drm, struct platform_device *pdev, > > > msm_devfreq_init(gpu); > > > - > > > gpu->aspace = gpu->funcs->create_address_space(gpu, pdev); > > > if (gpu->aspace == NULL) > > > @@ -1005,4 +1014,6 @@ 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); > > > > Resources should be released in reverse order, otherwise the cooling device > > could use resources that have already been freed. > > Why do you think this is not the correct order? If you are thinking > about devfreq struct, it is managed device resource. I did not check specifically if changing the frequency really uses any of the resources that are released previously, In any case it's not a good idea to allow other parts of the kernel to use a half initialized/torn down device. Even if it isn't a problem today someone could change the driver to use any of these resources (or add a new one) in a frequency change, without even thinking about the cooling device, just (rightfully) asuming that things are set up and torn down in a sane order.