From: Laurent Pinchart Date: Mon, 18 May 2015 10:53:48 +0300 Subject: [PATCH] v4l: uvcvideo: Fix incorrect bandwidth with Chicony device 04f2:b50b 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 Signed-off-by: Laurent Pinchart --- drivers/media/usb/uvc/uvc_video.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c index 20ccc9d315dc..f839654ea436 100644 --- a/drivers/media/usb/uvc/uvc_video.c +++ b/drivers/media/usb/uvc/uvc_video.c @@ -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) {