From: Christoph Hellwig <hch@lst.de>
To: Jonathan Marek <jonathan@marek.ca>
Cc: freedreno@lists.freedesktop.org, hch@lst.de,
Rob Clark <robdclark@gmail.com>, Sean Paul <sean@poorly.run>,
David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
"open list:DRM DRIVER FOR MSM ADRENO GPU"
<linux-arm-msm@vger.kernel.org>,
"open list:DRM DRIVER FOR MSM ADRENO GPU"
<dri-devel@lists.freedesktop.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [RESEND PATCH v2 4/5] drm/msm: add DRM_MSM_GEM_SYNC_CACHE for non-coherent cache maintenance
Date: Sat, 14 Nov 2020 17:24:06 +0100 [thread overview]
Message-ID: <20201114162406.GC24411@lst.de> (raw)
In-Reply-To: <20201114151717.5369-5-jonathan@marek.ca>
On Sat, Nov 14, 2020 at 10:17:12AM -0500, Jonathan Marek wrote:
> +void msm_gem_sync_cache(struct drm_gem_object *obj, uint32_t flags,
> + size_t range_start, size_t range_end)
> +{
> + struct msm_gem_object *msm_obj = to_msm_bo(obj);
> + struct device *dev = msm_obj->base.dev->dev;
> +
> + /* exit early if get_pages() hasn't been called yet */
> + if (!msm_obj->pages)
> + return;
> +
> + /* TODO: sync only the specified range */
> +
> + if (flags & MSM_GEM_SYNC_FOR_DEVICE) {
> + dma_sync_sg_for_device(dev, msm_obj->sgt->sgl,
> + msm_obj->sgt->nents, DMA_TO_DEVICE);
> + }
> +
> + if (flags & MSM_GEM_SYNC_FOR_CPU) {
> + dma_sync_sg_for_cpu(dev, msm_obj->sgt->sgl,
> + msm_obj->sgt->nents, DMA_FROM_DEVICE);
> + }
Splitting this helper from the only caller is rather strange, epecially
with the two unused arguments. And I think the way this is specified
to take a range, but ignoring it is actively dangerous. User space will
rely on it syncing everything sooner or later and then you are stuck.
So just define a sync all primitive for now, and if you really need a
range sync and have actually implemented it add a new ioctl for that.
next prev parent reply other threads:[~2020-11-14 16:24 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-14 15:17 [RESEND PATCH v2 0/5] drm/msm: support for host-cached BOs Jonathan Marek
2020-11-14 15:17 ` [RESEND PATCH v2 1/5] drm/msm: add MSM_BO_CACHED_COHERENT Jonathan Marek
2020-11-14 15:17 ` [RESEND PATCH v2 2/5] dma-direct: add dma_direct_bypass() to force direct ops Jonathan Marek
2020-11-14 16:21 ` Christoph Hellwig
2020-11-14 15:17 ` [RESEND PATCH v2 3/5] drm/msm: call dma_direct_bypass() Jonathan Marek
2020-11-14 16:21 ` Christoph Hellwig
2020-11-14 15:17 ` [RESEND PATCH v2 4/5] drm/msm: add DRM_MSM_GEM_SYNC_CACHE for non-coherent cache maintenance Jonathan Marek
2020-11-14 16:24 ` Christoph Hellwig [this message]
2020-11-14 18:46 ` Rob Clark
2020-11-14 18:54 ` Jonathan Marek
2020-11-14 19:39 ` Rob Clark
2020-11-14 20:07 ` Jonathan Marek
2020-11-14 20:48 ` Rob Clark
2020-11-16 17:33 ` Christoph Hellwig
2020-11-16 17:50 ` Rob Clark
2020-11-16 17:52 ` Jonathan Marek
2020-11-29 18:51 ` Rob Clark
2020-11-16 17:27 ` [Freedreno] " Jordan Crouse
2020-11-16 17:25 ` Jordan Crouse
2020-11-14 15:17 ` [RESEND PATCH v2 5/5] drm/msm: bump up the uapi version Jonathan Marek
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