From c4a98793a63c423c9e1af51822325969e23c16d4 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Tue, 18 Nov 2008 14:51:08 -0300 Subject: V4L/DVB (9646): em28xx: avoid allocating/dealocating memory on every control urb Before this patch, every register setup on em28xx were dynamically allocating a temporary buffer for control URB's to be handled. To avoid this ping-pong, use, instead a pre-allocated buffer. Also, be sure that read control URB's also use the buffer, instead of relying on a stack buffer. Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/em28xx/em28xx.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'drivers/media/video/em28xx/em28xx.h') diff --git a/drivers/media/video/em28xx/em28xx.h b/drivers/media/video/em28xx/em28xx.h index 8278117..1adf3d9 100644 --- a/drivers/media/video/em28xx/em28xx.h +++ b/drivers/media/video/em28xx/em28xx.h @@ -102,6 +102,9 @@ #define EM28XX_MIN_BUF 4 #define EM28XX_DEF_BUF 8 +/*Limits the max URB message size */ +#define URB_MAX_CTRL_SIZE 80 + /* Params for validated field */ #define EM28XX_BOARD_NOT_VALIDATED 1 #define EM28XX_BOARD_VALIDATED 0 @@ -451,6 +454,8 @@ struct em28xx { unsigned int *alt_max_pkt_size; /* array of wMaxPacketSize */ struct urb *urb[EM28XX_NUM_BUFS]; /* urb for isoc transfers */ char *transfer_buffer[EM28XX_NUM_BUFS]; /* transfer buffers for isoc transfer */ + char urb_buf[URB_MAX_CTRL_SIZE]; /* urb control msg buffer */ + /* helper funcs that call usb_control_msg */ int (*em28xx_write_regs) (struct em28xx *dev, u16 reg, char *buf, int len); -- cgit v1.1 From f2a2e4910502e866833732f31ee697d15b3e56fd Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Wed, 19 Nov 2008 06:17:44 -0300 Subject: V4L/DVB (9647): em28xx: void having two concurrent control URB's Now that we have a polling task for IR, there's a race condition, since IR can be polling while other operations are being doing. Also, we are now sharing the same urb_buf for both read and write control urb operations. So, we need a mutex. Thanks to Davin Heitmueller for warning me. Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/em28xx/em28xx.h | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/media/video/em28xx/em28xx.h') diff --git a/drivers/media/video/em28xx/em28xx.h b/drivers/media/video/em28xx/em28xx.h index 1adf3d9..5956e9b 100644 --- a/drivers/media/video/em28xx/em28xx.h +++ b/drivers/media/video/em28xx/em28xx.h @@ -433,6 +433,7 @@ struct em28xx { /* locks */ struct mutex lock; + struct mutex ctrl_urb_lock; /* protects urb_buf */ /* spinlock_t queue_lock; */ struct list_head inqueue, outqueue; wait_queue_head_t open, wait_frame, wait_stream; -- cgit v1.1