diff options
| author | Frank Schaefer <fschaefer.oss@googlemail.com> | 2012-11-08 14:11:51 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2012-12-22 18:13:11 -0200 |
| commit | c8e9d95b41f2a441b2af0a1899448dd45ad7632d (patch) | |
| tree | 0ba4efb4c2b5341591533b32bc374207432fcaf3 /drivers/media/usb | |
| parent | 7312f2c9fa22614acc787c064a0865840888d662 (diff) | |
[media] em28xx: set USB alternate settings for analog video bulk transfers properly
Extend function em28xx_set_alternate:
- use alternate setting 0 for bulk transfers as default
- respect module parameter 'alt'=0 for bulk transfers
- set max_packet_size to 512 bytes for bulk transfers
[mchehab@redhat.com: Fix a CodingStyle issue: don't break strings
into separate lines]
Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media/usb')
| -rw-r--r-- | drivers/media/usb/em28xx/em28xx-core.c | 23 |
1 files changed, 15 insertions, 8 deletions
diff --git a/drivers/media/usb/em28xx/em28xx-core.c b/drivers/media/usb/em28xx/em28xx-core.c index 3c40a1da69b..cdf4cd24007 100644 --- a/drivers/media/usb/em28xx/em28xx-core.c +++ b/drivers/media/usb/em28xx/em28xx-core.c @@ -805,21 +805,23 @@ int em28xx_resolution_set(struct em28xx *dev) return em28xx_scaler_set(dev, dev->hscale, dev->vscale); } +/* Set USB alternate setting for analog video */ int em28xx_set_alternate(struct em28xx *dev) { int errCode, prev_alt = dev->alt; int i; unsigned int min_pkt_size = dev->width * 2 + 4; - /* - * alt = 0 is used only for control messages, so, only values - * greater than 0 can be used for streaming. - */ - if (alt && alt < dev->num_alt) { + /* NOTE: for isoc transfers, only alt settings > 0 are allowed + for bulk transfers, use alt=0 as default value */ + dev->alt = 0; + if ((alt > 0) && (alt < dev->num_alt)) { em28xx_coredbg("alternate forced to %d\n", dev->alt); dev->alt = alt; goto set_alt; } + if (dev->analog_xfer_bulk) + goto set_alt; /* When image size is bigger than a certain value, the frame size should be increased, otherwise, only @@ -843,9 +845,14 @@ int em28xx_set_alternate(struct em28xx *dev) set_alt: if (dev->alt != prev_alt) { - em28xx_coredbg("minimum isoc packet size: %u (alt=%d)\n", - min_pkt_size, dev->alt); - dev->max_pkt_size = dev->alt_max_pkt_size_isoc[dev->alt]; + if (dev->analog_xfer_bulk) { + dev->max_pkt_size = 512; /* USB 2.0 spec */ + } else { /* isoc */ + em28xx_coredbg("minimum isoc packet size: %u (alt=%d)\n", + min_pkt_size, dev->alt); + dev->max_pkt_size = + dev->alt_max_pkt_size_isoc[dev->alt]; + } em28xx_coredbg("setting alternate %d with wMaxPacketSize=%u\n", dev->alt, dev->max_pkt_size); errCode = usb_set_interface(dev->udev, 0, dev->alt); |