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Commit d685a483 authored by Brett T. Warden's avatar Brett T. Warden Committed by Mauro Carvalho Chehab
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V4L/DVB (7013): bw-qcam: add module parameter 'force_init' to skip polite... 


V4L/DVB (7013): bw-qcam: add module parameter 'force_init' to skip polite auto-detection prior to direct initialization

Setting force_init=1 bypasses the friendly auto-detection by polling the
status register, and instead attempts to initialize the qcam directly.  Not
friendly to other parallel devices, but much more reliable than the
auto-detection.

Signed-off-by: default avatarBrett T. Warden <brett.warden@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@infradead.org>
parent a19602f2

drivers/media/video/bw-qcam.c

+9 −1
Original line number Diff line number Diff line
@@ -82,11 +82,16 @@ OTHER DEALINGS IN THE SOFTWARE. 
static unsigned int maxpoll=250;   /* Maximum busy-loop count for qcam I/O */

static unsigned int yieldlines=4;  /* Yield after this many during capture */

static int video_nr = -1;

static unsigned int force_init;		/* Whether to probe aggressively */



module_param(maxpoll, int, 0);

module_param(yieldlines, int, 0);

module_param(video_nr, int, 0);



/* Set force_init=1 to avoid detection by polling status register and

 * immediately attempt to initialize qcam */

module_param(force_init, int, 0);



static inline int read_lpstatus(struct qcam_device *q)

{

	return parport_read_status(q->pport);
@@ -331,6 +336,9 @@ static int qc_detect(struct qcam_device *q) 
	int count = 0;

	int i;



	if (force_init)

		return 1;



	lastreg = reg = read_lpstatus(q) & 0xf0;



	for (i = 0; i < 500; i++)
@@ -354,12 +362,12 @@ static int qc_detect(struct qcam_device *q) 


	/* Be (even more) liberal in what you accept...  */



/*	if (count > 30 && count < 200) */

	if (count > 20 && count < 400) {

		return 1;	/* found */

	} else {

		printk(KERN_ERR "No Quickcam found on port %s\n",

			q->pport->name);

		printk(KERN_DEBUG "Quickcam detection counter: %u\n", count);

		return 0;	/* not found */

	}

}