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[media] uvcvideo: Fix incorrect bandwidth with Chicony device 04f2:b50b

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The "TOSHIBA Web Camera - 5M" Chicony device (04f2:b50b) seems to
compute the bandwidth on 16 bits and erroneously sign-extend it to
32 bits, resulting in a huge bandwidth value. Detect and fix that
condition by setting the 16 MSBs to 0 when they're all equal to 1.

Reported-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
This commit is contained in:
Laurent Pinchart 2015-05-12 18:57:53 -03:00 committed by Mauro Carvalho Chehab
parent 7195f61b80
commit 37f85b276a
1 changed files with 8 additions and 0 deletions
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8
drivers/media/usb/uvc/uvc_video.c
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@ -119,6 +119,14 @@ static void uvc_fixup_video_ctrl(struct uvc_streaming *stream,
ctrl->dwMaxVideoFrameSize =
frame->dwMaxVideoFrameBufferSize;
/* The "TOSHIBA Web Camera - 5M" Chicony device (04f2:b50b) seems to
* compute the bandwidth on 16 bits and erroneously sign-extend it to
* 32 bits, resulting in a huge bandwidth value. Detect and fix that
* condition by setting the 16 MSBs to 0 when they're all equal to 1.
*/
if ((ctrl->dwMaxPayloadTransferSize & 0xffff0000) == 0xffff0000)
ctrl->dwMaxPayloadTransferSize &= ~0xffff0000;
if (!(format->flags & UVC_FMT_FLAG_COMPRESSED) &&
stream->dev->quirks & UVC_QUIRK_FIX_BANDWIDTH &&
stream->intf->num_altsetting > 1) {