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Subject[PATCH] bw-qcam: Adds module parameter 'aggressive' to skip polite auto-detection prior to direct initialization.
Date
Setting aggressive=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: Brett T. Warden <brett.warden@gmail.com>
---
drivers/media/video/bw-qcam.c | 10 +++++++++-
1 files changed, 9 insertions(+), 1 deletions(-)

diff --git a/drivers/media/video/bw-qcam.c b/drivers/media/video/bw-qcam.c
index 5842352..b74a9cb 100644
--- a/drivers/media/video/bw-qcam.c
+++ b/drivers/media/video/bw-qcam.c
@@ -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 aggressive; /* Whether to probe aggressively */

module_param(maxpoll, int, 0);
module_param(yieldlines, int, 0);
module_param(video_nr, int, 0);

+/* Set aggressive=1 to avoid detection by polling status register and
+ * immediately attempt to initialize qcam */
+module_param(aggressive, 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 (aggressive)
+ 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 */
}
}
--
1.5.3.7


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