diff options
Diffstat (limited to 'drivers/char/bw-qcam.c')
| -rw-r--r-- | drivers/char/bw-qcam.c | 167 |
1 files changed, 146 insertions, 21 deletions
diff --git a/drivers/char/bw-qcam.c b/drivers/char/bw-qcam.c index 9f8935e8b..87821edf8 100644 --- a/drivers/char/bw-qcam.c +++ b/drivers/char/bw-qcam.c @@ -5,6 +5,28 @@ * * Video4Linux conversion work by Alan Cox. * Parport compatibility by Phil Blundell. + * Busy loop avoidance by Mark Cooke. + * + * Module parameters: + * + * maxpoll=<1 - 5000> + * + * When polling the QuickCam for a response, busy-wait for a + * maximum of this many loops. The default of 250 gives little + * impact on interactive response. + * + * NOTE: If this parameter is set too high, the processor + * will busy wait until this loop times out, and then + * slowly poll for a further 5 seconds before failing + * the transaction. You have been warned. + * + * yieldlines=<1 - 250> + * + * When acquiring a frame from the camera, the data gathering + * loop will yield back to the scheduler after completing + * this many lines. The default of 4 provides a trade-off + * between increased frame acquisition time and impact on + * interactive response. */ /* qcam-lib.c -- Library for programming with the Connectix QuickCam. @@ -58,6 +80,14 @@ OTHER DEALINGS IN THE SOFTWARE. #include "bw-qcam.h" +#if LINUX_VERSION_CODE >= 0x020117 +MODULE_PARM(maxpoll,"i"); +MODULE_PARM(yieldlines,"i"); +#endif + +static unsigned int maxpoll=250; /* Maximum busy-loop count for qcam I/O */ +static unsigned int yieldlines=4; /* Yield after this many during capture */ + extern __inline__ int read_lpstatus(struct qcam_device *q) { return parport_read_status(q->pport); @@ -154,6 +184,7 @@ static struct qcam_device *qcam_init(struct parport *port) q->top = 1; q->left = 14; q->mode = -1; + q->status = QC_PARAM_CHANGE; return q; } @@ -209,14 +240,17 @@ static int qc_waithand(struct qcam_device *q, int val) { /* 1000 is enough spins on the I/O for all normal cases, at that point we start to poll slowly - until the camera wakes up */ + until the camera wakes up. However, we are + busy blocked until the camera responds, so + setting it lower is much better for interactive + response. */ - if(runs++>1000) + if(runs++>maxpoll) { current->state=TASK_INTERRUPTIBLE; - schedule_timeout(HZ/10); + schedule_timeout(HZ/200); } - if(runs>1050) + if(runs>(maxpoll+1000)) /* 5 seconds */ return -1; } } @@ -226,14 +260,17 @@ static int qc_waithand(struct qcam_device *q, int val) { /* 1000 is enough spins on the I/O for all normal cases, at that point we start to poll slowly - until the camera wakes up */ + until the camera wakes up. However, we are + busy blocked until the camera responds, so + setting it lower is much better for interactive + response. */ - if(runs++>1000) + if(runs++>maxpoll) { current->state=TASK_INTERRUPTIBLE; - schedule_timeout(HZ/10); + schedule_timeout(HZ/200); } - if(runs++>1050) /* 5 seconds */ + if(runs++>(maxpoll+1000)) /* 5 seconds */ return -1; } } @@ -256,14 +293,17 @@ static unsigned int qc_waithand2(struct qcam_device *q, int val) status = read_lpdata(q); /* 1000 is enough spins on the I/O for all normal cases, at that point we start to poll slowly - until the camera wakes up */ + until the camera wakes up. However, we are + busy blocked until the camera responds, so + setting it lower is much better for interactive + response. */ - if(runs++>1000) + if(runs++>maxpoll) { current->state=TASK_INTERRUPTIBLE; - schedule_timeout(HZ/10); + schedule_timeout(HZ/200); } - if(runs++>1050) /* 5 seconds */ + if(runs++>(maxpoll+1000)) /* 5 seconds */ return 0; } while ((status & 1) != val); @@ -287,7 +327,7 @@ static int qc_detect(struct qcam_device *q) lastreg = reg = read_lpstatus(q) & 0xf0; - for (i = 0; i < 300; i++) + for (i = 0; i < 500; i++) { reg = read_lpstatus(q) & 0xf0; if (reg != lastreg) @@ -296,9 +336,20 @@ static int qc_detect(struct qcam_device *q) mdelay(2); } - /* Be liberal in what you accept... */ - if (count > 30 && count < 200) +#if 0 + /* Force camera detection during testing. Sometimes the camera + won't be flashing these bits. Possibly unloading the module + in the middle of a grab? Or some timeout condition? + I've seen this parameter as low as 19 on my 450Mhz box - mpc */ + printk("Debugging: QCam detection counter <30-200 counts as detected>: %d\n", count); + return 1; +#endif + + /* Be (even more) liberal in what you accept... */ + +/* if (count > 30 && count < 200) */ + if (count > 20 && count < 300) return 1; /* found */ else return 0; /* not found */ @@ -352,6 +403,8 @@ static void qc_reset(struct qcam_device *q) static int qc_setscanmode(struct qcam_device *q) { + int old_mode = q->mode; + switch (q->transfer_scale) { case 1: @@ -383,6 +436,10 @@ static int qc_setscanmode(struct qcam_device *q) case QC_UNIDIR: break; } + + if (q->mode != old_mode) + q->status |= QC_PARAM_CHANGE; + return 0; } @@ -434,8 +491,11 @@ void qc_set(struct qcam_device *q) qc_command(q, q->contrast); qc_command(q, 0x1f); qc_command(q, q->whitebal); -} + /* Clear flag that we must update the grabbing parameters on the camera + before we grab the next frame */ + q->status &= (~QC_PARAM_CHANGE); +} /* Qc_readbytes reads some bytes from the QC and puts them in the supplied buffer. It returns the number of bytes read, @@ -539,7 +599,7 @@ extern __inline__ int qc_readbytes(struct qcam_device *q, char buffer[]) long qc_capture(struct qcam_device * q, char *buf, unsigned long len) { - int i, j, k; + int i, j, k, yield; int bytes; int linestotrans, transperline; int divisor; @@ -575,7 +635,7 @@ long qc_capture(struct qcam_device * q, char *buf, unsigned long len) q->transfer_scale; transperline = (transperline + divisor - 1) / divisor; - for (i = 0; i < linestotrans; i++) + for (i = 0, yield = yieldlines; i < linestotrans; i++) { for (pixels_read = j = 0; j < transperline; j++) { @@ -599,6 +659,18 @@ long qc_capture(struct qcam_device * q, char *buf, unsigned long len) pixels_read += bytes; } (void) qc_readbytes(q, 0); /* reset state machine */ + + /* Grabbing an entire frame from the quickcam is a lengthy + process. We don't (usually) want to busy-block the + processor for the entire frame. yieldlines is a module + parameter. If we yield every line, the minimum frame + time will be 240 / 200 = 1.2 seconds. The compile-time + default is to yield every 4 lines. */ + if (i >= yield) { + current->state=TASK_INTERRUPTIBLE; + schedule_timeout(HZ/200); + yield = i + yieldlines; + } } if ((q->port_mode & QC_MODE_MASK) == QC_BIDIR) @@ -745,9 +817,12 @@ static int qcam_ioctl(struct video_device *dev, unsigned int cmd, void *arg) qcam->bpp = p.depth; qc_setscanmode(qcam); - parport_claim_or_block(qcam->pdev); + qcam->status |= QC_PARAM_CHANGE; + +/* parport_claim_or_block(qcam->pdev); qc_set(qcam); parport_release(qcam->pdev); +*/ return 0; } case VIDIOCSWIN: @@ -779,6 +854,11 @@ static int qcam_ioctl(struct video_device *dev, unsigned int cmd, void *arg) qcam->transfer_scale = 1; } qc_setscanmode(qcam); + + /* We must update the camera before we grab. We could + just have changed the grab size */ + qcam->status |= QC_PARAM_CHANGE; + /* Ok we figured out what to use from our wide choice */ return 0; } @@ -824,11 +904,15 @@ static long qcam_read(struct video_device *v, char *buf, unsigned long count, i parport_claim_or_block(qcam->pdev); /* Probably should have a semaphore against multiple users */ qc_reset(qcam); + + /* Update the camera parameters if we need to */ + if (qcam->status & QC_PARAM_CHANGE) + qc_set(qcam); + len=qc_capture(qcam, buf,count); parport_release(qcam->pdev); return len; } - static struct video_device qcam_template= { @@ -902,14 +986,55 @@ void close_bwqcam(struct qcam_device *qcam) kfree(qcam); } +/* The parport parameter controls which parports will be scanned. + * Scanning all parports causes some printers to print a garbage page. + * -- March 14, 1999 Billy Donahue <billy@escape.com> */ +#ifdef MODULE +static char *parport[MAX_CAMS] = { NULL, }; +MODULE_PARM(parport, "1-" __MODULE_STRING(MAX_CAMS) "s"); +#endif + #ifdef MODULE int init_module(void) { struct parport *port; - + int n; + if(parport[0] && strncmp(parport[0], "auto", 4)){ + /* user gave parport parameters */ + for(n=0; parport[n] && n<MAX_CAMS; n++){ + char *ep; + unsigned long r; + r = simple_strtoul(parport[n], &ep, 0); + if(ep == parport[n]){ + printk(KERN_ERR + "bw-qcam: bad port specifier \"%s\"\n", + parport[n]); + continue; + } + for (port=parport_enumerate(); port; port=port->next){ + if(r!=port->number) + continue; + init_bwqcam(port); + break; + } + } + return (num_cams)?0:-ENODEV; + } + /* no parameter or "auto" */ for (port = parport_enumerate(); port; port=port->next) init_bwqcam(port); + /* Do some sanity checks on the module parameters. */ + if (maxpoll > 5000) { + printk("Connectix Quickcam max-poll was above 5000. Using 5000.\n"); + maxpoll = 5000; + } + + if (yieldlines < 1) { + printk("Connectix Quickcam yieldlines was less than 1. Using 1.\n"); + yieldlines = 1; + } + return (num_cams)?0:-ENODEV; } |