From 8df59213e66592abbfeba4cdc595aac994dfce7a Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Wed, 19 Sep 2007 01:44:18 -0400 Subject: cafe_ccic: default to allocating DMA buffers at probe time From: Andres Salomon By default, we allocate DMA buffers when actually reading from the video capture device. On a system with 128MB or 256MB of ram, it's very easy for that memory to quickly become fragmented. We've had users report having 30+MB of memory free, but the cafe_ccic driver is still unable to allocate DMA buffers. Our workaround has been to make use of the 'alloc_bufs_at_load' parameter to allocate DMA buffers during device probing. This patch makes DMA buffer allocation happen during device probe by default, and changes the parameter to 'alloc_bufs_at_read'. The camera hardware is there, if the cafe_ccic driver is enabled/loaded it should do its best to ensure that the camera is actually usable; delaying DMA buffer allocation saves an insignicant amount of memory, and causes the driver to be much less useful. Signed-off-by: Andres Salomon Acked-by: Jonathan Corbet Signed-off-by: Mauro Carvalho Chehab --- linux/drivers/media/video/cafe_ccic.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/linux/drivers/media/video/cafe_ccic.c b/linux/drivers/media/video/cafe_ccic.c index 3595fde11..5c69b43fa 100644 --- a/linux/drivers/media/video/cafe_ccic.c +++ b/linux/drivers/media/video/cafe_ccic.c @@ -63,13 +63,13 @@ MODULE_SUPPORTED_DEVICE("Video"); */ #define MAX_DMA_BUFS 3 -static int alloc_bufs_at_load = 0; -module_param(alloc_bufs_at_load, bool, 0444); -MODULE_PARM_DESC(alloc_bufs_at_load, - "Non-zero value causes DMA buffers to be allocated at module " - "load time. This increases the chances of successfully getting " - "those buffers, but at the cost of nailing down the memory from " - "the outset."); +static int alloc_bufs_at_read = 0; +module_param(alloc_bufs_at_read, bool, 0444); +MODULE_PARM_DESC(alloc_bufs_at_read, + "Non-zero value causes DMA buffers to be allocated when the " + "video capture device is read, rather than at module load " + "time. This saves memory, but decreases the chances of " + "successfully getting those buffers."); static int n_dma_bufs = 3; module_param(n_dma_bufs, uint, 0644); @@ -1509,7 +1509,7 @@ static int cafe_v4l_release(struct inode *inode, struct file *filp) } if (cam->users == 0) { cafe_ctlr_power_down(cam); - if (! alloc_bufs_at_load) + if (alloc_bufs_at_read) cafe_free_dma_bufs(cam); } mutex_unlock(&cam->s_mutex); @@ -2168,7 +2168,7 @@ static int cafe_pci_probe(struct pci_dev *pdev, /* * If so requested, try to get our DMA buffers now. */ - if (alloc_bufs_at_load) { + if (!alloc_bufs_at_read) { if (cafe_alloc_dma_bufs(cam, 1)) cam_warn(cam, "Unable to alloc DMA buffers at load" " will try again later."); -- cgit v1.2.3