This is a note to let you know that I've just added the patch titled

drm/cma-helper: Release non-coherent memory with dma_free_noncoherent()

to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summ...

The filename of the patch is: drm-cma-helper-release-non-coherent-memory-with-dma_free_noncoherent.patch and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 995f54ea962e03ec08b8bc6a4fe11a32b420edd3 Mon Sep 17 00:00:00 2001

From: Thomas Zimmermann tzimmermann@suse.de Date: Thu, 8 Jul 2021 19:51:46 +0200 Subject: drm/cma-helper: Release non-coherent memory with dma_free_noncoherent()

From: Thomas Zimmermann tzimmermann@suse.de

commit 995f54ea962e03ec08b8bc6a4fe11a32b420edd3 upstream.

The GEM CMA helpers allocate non-coherent (i.e., cached) backing storage with dma_alloc_noncoherent(), but release it with dma_free_wc(). Fix this with a call to dma_free_noncoherent(). Writecombining storage is still released with dma_free_wc().

Signed-off-by: Thomas Zimmermann tzimmermann@suse.de Fixes: cf8ccbc72d61 ("drm: Add support for GEM buffers backed by non-coherent memory") Acked-by: Paul Cercueil paul@crapouillou.net Cc: Thomas Zimmermann tzimmermann@suse.de Cc: Maarten Lankhorst maarten.lankhorst@linux.intel.com Cc: Maxime Ripard mripard@kernel.org Cc: David Airlie airlied@linux.ie Cc: Daniel Vetter daniel@ffwll.ch Cc: dri-devel@lists.freedesktop.org Cc: stable@vger.kernel.org # v5.14+ Link: https://patchwork.freedesktop.org/patch/msgid/20210708175146.10618-1-tzimmer... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/drm_gem_cma_helper.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/drm_gem_cma_helper.c +++ b/drivers/gpu/drm/drm_gem_cma_helper.c @@ -210,8 +210,13 @@ void drm_gem_cma_free_object(struct drm_ dma_buf_vunmap(gem_obj->import_attach->dmabuf, &map); drm_prime_gem_destroy(gem_obj, cma_obj->sgt); } else if (cma_obj->vaddr) { - dma_free_wc(gem_obj->dev->dev, cma_obj->base.size, - cma_obj->vaddr, cma_obj->paddr); + if (cma_obj->map_noncoherent) + dma_free_noncoherent(gem_obj->dev->dev, cma_obj->base.size, + cma_obj->vaddr, cma_obj->paddr, + DMA_TO_DEVICE); + else + dma_free_wc(gem_obj->dev->dev, cma_obj->base.size, + cma_obj->vaddr, cma_obj->paddr); }

drm_gem_object_release(gem_obj);

Patches currently in stable-queue which might be from tzimmermann@suse.de are

queue-5.15/drm-cma-helper-release-non-coherent-memory-with-dma_free_noncoherent.patch