Since commit 6d3163ce86dd386b4f7bda80241d7fea2bc0bb1d, "mm: check if any
page in a pageblock is reserved before marking it MIGRATE_RESERVE", the
OMAP1 camera driver behaviour while in videobuf-dma-contig mode can be
observed as much more stable than before. Once all application programs
are started up and nothing unexpected happens in the system, consecutive
device open()s tend to succeed with almost 100% reliability.
While the result is still not perfect, still prone to occasional -ENOMEM
failures, I think there is no longer a need to fall back to more
reliable but less effective, more resource hungry videobuf-dma-sg mode
if a single open() fails, as long as users are still able to switch
DMA modes from user space over the driver provided sysfs interface,
should videobuf-dma-contig mode still happen to keep failing for them.
Tested on Amstrad Delta.
Signed-off-by: Janusz Krzysztofik <jkrzyszt@xxxxxxxxxxxx>
---
Hi,
While this patch is not a classic fix, not correcting anything that
could be considered as a bug or regression, it is a simple consequence
of unexpected but very welcome enhancement introduced during this merge
window, so I hope it can be accepted in the rc cycle for that reason.
Moreover, it provides no new, but simplifies existing code by removing
no longer needed bits.
Thanks,
Janusz
drivers/media/video/omap1_camera.c | 37 +------------------------------------
1 file changed, 1 insertion(+), 36 deletions(-)
--- git/drivers/media/video/omap1_camera.c.orig 2011-06-06 18:07:54.000000000 +0200
+++ git/drivers/media/video/omap1_camera.c 2011-06-09 12:04:09.000000000 +0200
@@ -172,9 +172,6 @@ struct omap1_cam_dev {
struct omap1_cam_buf *ready;
enum omap1_cam_vb_mode vb_mode;
- int (*mmap_mapper)(struct videobuf_queue *q,
- struct videobuf_buffer *buf,
- struct vm_area_struct *vma);
u32 reg_cache[0];
};
@@ -1352,28 +1349,6 @@ static int omap1_cam_try_fmt(struct soc_
static bool sg_mode;
-/*
- * Local mmap_mapper wrapper,
- * used for detecting videobuf-dma-contig buffer allocation failures
- * and switching to videobuf-dma-sg automatically for future attempts.
- */
-static int omap1_cam_mmap_mapper(struct videobuf_queue *q,
- struct videobuf_buffer *buf,
- struct vm_area_struct *vma)
-{
- struct soc_camera_device *icd = q->priv_data;
- struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
- struct omap1_cam_dev *pcdev = ici->priv;
- int ret;
-
- ret = pcdev->mmap_mapper(q, buf, vma);
-
- if (ret == -ENOMEM)
- sg_mode = true;
-
- return ret;
-}
-
static void omap1_cam_init_videobuf(struct videobuf_queue *q,
struct soc_camera_device *icd)
{
@@ -1391,18 +1366,8 @@ static void omap1_cam_init_videobuf(stru
V4L2_BUF_TYPE_VIDEO_CAPTURE, V4L2_FIELD_NONE,
sizeof(struct omap1_cam_buf), icd, &icd->video_lock);
- /* use videobuf mode (auto)selected with the module parameter */
+ /* use videobuf mode selected with the module parameter */
pcdev->vb_mode = sg_mode ? OMAP1_CAM_DMA_SG : OMAP1_CAM_DMA_CONTIG;
-
- /*
- * Ensure we substitute the videobuf-dma-contig version of the
- * mmap_mapper() callback with our own wrapper, used for switching
- * automatically to videobuf-dma-sg on buffer allocation failure.
- */
- if (!sg_mode && q->int_ops->mmap_mapper != omap1_cam_mmap_mapper) {
- pcdev->mmap_mapper = q->int_ops->mmap_mapper;
- q->int_ops->mmap_mapper = omap1_cam_mmap_mapper;
- }
}
static int omap1_cam_reqbufs(struct soc_camera_device *icd,
--
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