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SubjectRe: [PATCH v2 03/43] drm/rockchip: Respect page offset for PRIME mmap calls
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在 2018/1/26 21:16, Thierry Escande 写道:
> From: Ørjan Eide <orjan.eide@arm.com>
>
> When mapping external DMA-bufs through the PRIME mmap call, we might be
> given an offset which has to be respected. However for the internal DRM
> GEM mmap path, we have to ignore the fake mmap offset used to identify
> the buffer only. Currently the code always zeroes out vma->vm_pgoff,
> which breaks the former.
>
> This patch fixes the problem by moving the vm_pgoff assignment to a
> function that is used only for GEM mmap path, so that the PRIME path
> retains the original offset.
>
> Cc: Daniel Kurtz <djkurtz@chromium.org>
> Signed-off-by: Ørjan Eide <orjan.eide@arm.com>
> Signed-off-by: Tomasz Figa <tfiga@chromium.org>
> Signed-off-by: Sean Paul <seanpaul@chromium.org>
> Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
> Tested-by: Heiko Stuebner <heiko@sntech.de>
> ---
> drivers/gpu/drm/rockchip/rockchip_drm_gem.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
> index 5d52020deca1..074db7a92809 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
> @@ -264,7 +264,6 @@ static int rockchip_drm_gem_object_mmap(struct drm_gem_object *obj,
> * VM_PFNMAP flag that was set by drm_gem_mmap_obj()/drm_gem_mmap().
> */
> vma->vm_flags &= ~VM_PFNMAP;
> - vma->vm_pgoff = 0;
>
> if (rk_obj->pages)
> ret = rockchip_drm_gem_object_mmap_iommu(obj, vma);
> @@ -299,6 +298,12 @@ int rockchip_gem_mmap(struct file *filp, struct vm_area_struct *vma)
> if (ret)
> return ret;
>
> + /*
> + * Set vm_pgoff (used as a fake buffer offset by DRM) to 0 and map the
> + * whole buffer from the start.
> + */
> + vma->vm_pgoff = 0;
> +
> obj = vma->vm_private_data;
>
> return rockchip_drm_gem_object_mmap(obj, vma);
>

Reviewed-by: Sandy huang <hjc@rock-chips.com>

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