From: Thomas Zimmermann <tzimmermann@suse.de>
To: "Adrián Larumbe" <adrian.larumbe@collabora.com>,
"Qiang Yu" <yuq825@gmail.com>,
"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
"Maxime Ripard" <mripard@kernel.org>,
"David Airlie" <airlied@gmail.com>,
"Daniel Vetter" <daniel@ffwll.ch>,
"Boris Brezillon" <boris.brezillon@collabora.com>,
"Rob Herring" <robh@kernel.org>,
"Steven Price" <steven.price@arm.com>,
"Sumit Semwal" <sumit.semwal@linaro.org>,
"Christian Koenig=" <christian.koenig@amd.com>,
"Dmitry Osipenko" <dmitry.osipenko@collabora.com>,
"Zack Rusin" <zack.rusin@broadcom.com>
Cc: kernel@collabora.com, dri-devel@lists.freedesktop.org,
lima@lists.freedesktop.org, linux-kernel@vger.kernel.org,
linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org
Subject: Re: [PATCH v3 0/2] drm: Fix dma_resv deadlock at drm object pin time
Date: Thu, 2 May 2024 13:51:16 +0200 [thread overview]
Message-ID: <84a5f7b6-d20a-4c69-83a8-d8394fea2b68@suse.de> (raw)
In-Reply-To: <20240501065650.2809530-1-adrian.larumbe@collabora.com>
Hi,
ignoring my r-b on patch 1, I'd like to rethink the current patches in
general.
I think drm_gem_shmem_pin() should become the locked version of _pin(),
so that drm_gem_shmem_object_pin() can call it directly. The existing
_pin_unlocked() would not be needed any longer. Same for the _unpin()
functions. This change would also fix the consistency with the semantics
of the shmem _vmap() functions, which never take reservation locks.
There are only two external callers of drm_gem_shmem_pin(): the test
case and panthor. These assume that drm_gem_shmem_pin() acquires the
reservation lock. The test case should likely call drm_gem_pin()
instead. That would acquire the reservation lock and the test would
validate that shmem's pin helper integrates well into the overall GEM
framework. The way panthor uses drm_gem_shmem_pin() looks wrong to me.
For now, it could receive a wrapper that takes the lock and that's it.
Best regards
Thomas
Am 01.05.24 um 08:55 schrieb Adrián Larumbe:
> This is v3 of https://lore.kernel.org/dri-devel/20240424090429.57de7d1c@collabora.com/
>
> The goal of this patch series is fixing a deadlock upon locking the dma reservation
> of a DRM gem object when pinning it, at a prime import operation.
>
> Changes from v2:
> - Removed comment explaining reason why an already-locked
> pin function replaced the locked variant inside Panfrost's
> object pin callback.
> - Moved already-assigned attachment warning into generic
> already-locked gem object pin function
>
> Adrián Larumbe (2):
> drm/panfrost: Fix dma_resv deadlock at drm object pin time
> drm/gem-shmem: Add import attachment warning to locked pin function
>
> drivers/gpu/drm/drm_gem_shmem_helper.c | 2 ++
> drivers/gpu/drm/lima/lima_gem.c | 2 +-
> drivers/gpu/drm/panfrost/panfrost_gem.c | 2 +-
> 3 files changed, 4 insertions(+), 2 deletions(-)
>
>
> base-commit: 75b68f22e39aafb22f3d8e3071e1aba73560788c
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)
next prev parent reply other threads:[~2024-05-02 11:51 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-01 6:55 [PATCH v3 0/2] drm: Fix dma_resv deadlock at drm object pin time Adrián Larumbe
2024-05-01 6:55 ` [PATCH v3 1/2] drm/panfrost: " Adrián Larumbe
2024-05-02 7:09 ` Boris Brezillon
2024-05-02 11:14 ` Thomas Zimmermann
2024-05-01 6:56 ` [PATCH v3 2/2] drm/gem-shmem: Add import attachment warning to locked pin function Adrián Larumbe
2024-05-02 7:01 ` Boris Brezillon
2024-05-02 11:51 ` Thomas Zimmermann [this message]
2024-05-02 11:59 ` [PATCH v3 0/2] drm: Fix dma_resv deadlock at drm object pin time Boris Brezillon
2024-05-02 12:00 ` Boris Brezillon
2024-05-02 12:18 ` Thomas Zimmermann
2024-05-17 18:16 ` Adrián Larumbe
2024-05-21 16:18 ` Boris Brezillon
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