[04/41] drm/rockchip: Respect page offset for PRIME mmap calls

Message ID 20170310043305.17216-5-seanpaul@chromium.org
State New
Headers show

Commit Message

Sean Paul March 10, 2017, 4:32 a.m.
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.

BUG=chrome-os-partner:56615
TEST=graphics_GLBench

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>
---
 drivers/gpu/drm/rockchip/rockchip_drm_gem.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

Comments

Heiko Stuebner Dec. 12, 2017, 4:58 p.m. | #1
Hi,

Am Donnerstag, 9. März 2017, 23:32:19 CET schrieb Sean Paul:
> 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.
> 
> BUG=chrome-os-partner:56615
> TEST=graphics_GLBench

Unneeded chromeos-cruft.

> 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>

With the same testas patch 3  (rk3328 + lima)
Tested-by: Heiko Stuebner <heiko@sntech.de>

Patch

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
index 5dffe276d2a7..7fa2cb77bdc0 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
@@ -263,7 +263,6 @@  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);
@@ -298,6 +297,12 @@  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);