3 files changed, 40 insertions, 4 deletions

diff --git a/drivers/media/video/uvc/uvc_driver.c b/drivers/media/video/uvc/uvc_driver.c
index ebcd5bf0edb7..22e2783ac555 100644
--- a/drivers/media/video/uvc/uvc_driver.c
+++ b/drivers/media/video/uvc/uvc_driver.c
@@ -1861,6 +1861,15 @@ static struct usb_device_id uvc_ids[] = {
           .bInterfaceSubClass   = 1,
           .bInterfaceProtocol   = 0,
           .driver_info          = UVC_QUIRK_STREAM_NO_FID },
+        /* ViMicro */
+        { .match_flags          = USB_DEVICE_ID_MATCH_VENDOR
+                                | USB_DEVICE_ID_MATCH_INT_INFO,
+          .idVendor             = 0x0ac8,
+          .idProduct            = 0x0000,
+          .bInterfaceClass      = USB_CLASS_VIDEO,
+          .bInterfaceSubClass   = 1,
+          .bInterfaceProtocol   = 0,
+          .driver_info          = UVC_QUIRK_FIX_BANDWIDTH },
         /* MT6227 */
         { .match_flags          = USB_DEVICE_ID_MATCH_DEVICE
                                 | USB_DEVICE_ID_MATCH_INT_INFO,
diff --git a/drivers/media/video/uvc/uvc_video.c b/drivers/media/video/uvc/uvc_video.c
index 0789ba381fc1..a95e17329c5b 100644
--- a/drivers/media/video/uvc/uvc_video.c
+++ b/drivers/media/video/uvc/uvc_video.c
@@ -61,7 +61,7 @@ int uvc_query_ctrl(struct uvc_device *dev, __u8 query, __u8 unit,
         return 0;
 }
 
-static void uvc_fixup_buffer_size(struct uvc_video_device *video,
+static void uvc_fixup_video_ctrl(struct uvc_video_device *video,
         struct uvc_streaming_control *ctrl)
 {
         struct uvc_format *format;
@@ -84,6 +84,31 @@ static void uvc_fixup_buffer_size(struct uvc_video_device *video,
               video->dev->uvc_version < 0x0110))
                 ctrl->dwMaxVideoFrameSize =
                         frame->dwMaxVideoFrameBufferSize;
+
+        if (video->dev->quirks & UVC_QUIRK_FIX_BANDWIDTH &&
+            video->streaming->intf->num_altsetting > 1) {
+                u32 interval;
+                u32 bandwidth;
+
+                interval = (ctrl->dwFrameInterval > 100000)
+                         ? ctrl->dwFrameInterval
+                         : frame->dwFrameInterval[0];
+
+                /* Compute a bandwidth estimation by multiplying the frame
+                 * size by the number of video frames per second, divide the
+                 * result by the number of USB frames (or micro-frames for
+                 * high-speed devices) per second and add the UVC header size
+                 * (assumed to be 12 bytes long).
+                 */
+                bandwidth = frame->wWidth * frame->wHeight / 8 * format->bpp;
+                bandwidth *= 10000000 / interval + 1;
+                bandwidth /= 1000;
+                if (video->dev->udev->speed == USB_SPEED_HIGH)
+                        bandwidth /= 8;
+                bandwidth += 12;
+
+                ctrl->dwMaxPayloadTransferSize = bandwidth;
+        }
 }
 
 static int uvc_get_video_ctrl(struct uvc_video_device *video,
@@ -158,10 +183,11 @@ static int uvc_get_video_ctrl(struct uvc_video_device *video,
                 ctrl->bMaxVersion = 0;
         }
 
-        /* Some broken devices return a null or wrong dwMaxVideoFrameSize.
-         * Try to get the value from the format and frame descriptors.
+        /* Some broken devices return null or wrong dwMaxVideoFrameSize and
+         * dwMaxPayloadTransferSize fields. Try to get the value from the
+         * format and frame descriptors.
          */
-        uvc_fixup_buffer_size(video, ctrl);
+        uvc_fixup_video_ctrl(video, ctrl);
         ret = 0;
 
 out:
diff --git a/drivers/media/video/uvc/uvcvideo.h b/drivers/media/video/uvc/uvcvideo.h
index 6f55c4d49cf4..e5014e668f99 100644
--- a/drivers/media/video/uvc/uvcvideo.h
+++ b/drivers/media/video/uvc/uvcvideo.h
@@ -314,6 +314,7 @@ struct uvc_xu_control {
 #define UVC_QUIRK_STREAM_NO_FID         0x00000010
 #define UVC_QUIRK_IGNORE_SELECTOR_UNIT  0x00000020
 #define UVC_QUIRK_PRUNE_CONTROLS        0x00000040
+#define UVC_QUIRK_FIX_BANDWIDTH         0x00000080
 
 /* Format flags */
 #define UVC_FMT_FLAG_COMPRESSED         0x00000001