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authorGravatar Laurent Pinchart <laurent.pinchart@ideasonboard.com> 2023-05-05 14:45:24 +0300
committerGravatar Mauro Carvalho Chehab <mchehab@kernel.org> 2023-06-09 14:11:52 +0100
commitc9d597b9b7ef9ffcb54051f04798b608edc6850c (patch)
tree0b6973e8fd3c2d74bcf641d12a29d1a396524431 /drivers/media
parentmedia: uvcvideo: Use clamp() to replace manual implementation (diff)
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media: uvcvideo: Reorganize format descriptor parsing
Format descriptor parsing has grown over time and now mixes parsing of frame intervals with various quirk handling. Reorganize it to make the code easier to follow, by parsing frame intervals first, and then applying fixes and quirks. No functional change is intended. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Ricardo Ribalda <ribalda@chromium.org> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Diffstat (limited to 'drivers/media')
-rw-r--r--drivers/media/usb/uvc/uvc_driver.c40
1 files changed, 25 insertions, 15 deletions
diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
index 9f89c781e885..ef9066dcf535 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -405,8 +405,27 @@ static int uvc_parse_format(struct uvc_device *dev,
get_unaligned_le32(&buffer[17]);
frame->bFrameIntervalType = buffer[21];
}
+
+ /*
+ * Copy the frame intervals.
+ *
+ * Some bogus devices report dwMinFrameInterval equal to
+ * dwMaxFrameInterval and have dwFrameIntervalStep set to
+ * zero. Setting all null intervals to 1 fixes the problem and
+ * some other divisions by zero that could happen.
+ */
frame->dwFrameInterval = *intervals;
+ for (i = 0; i < n; ++i) {
+ interval = get_unaligned_le32(&buffer[26+4*i]);
+ *(*intervals)++ = interval ? interval : 1;
+ }
+
+ /*
+ * Apply more fixes, quirks and workarounds to handle incorrect
+ * or broken descriptors.
+ */
+
/*
* Several UVC chipsets screw up dwMaxVideoFrameBufferSize
* completely. Observed behaviours range from setting the
@@ -420,27 +439,18 @@ static int uvc_parse_format(struct uvc_device *dev,
frame->dwMaxVideoFrameBufferSize = format->bpp
* frame->wWidth * frame->wHeight / 8;
- /*
- * Some bogus devices report dwMinFrameInterval equal to
- * dwMaxFrameInterval and have dwFrameIntervalStep set to
- * zero. Setting all null intervals to 1 fixes the problem and
- * some other divisions by zero that could happen.
- */
- for (i = 0; i < n; ++i) {
- interval = get_unaligned_le32(&buffer[26+4*i]);
- *(*intervals)++ = interval ? interval : 1;
- }
-
- /*
- * Make sure that the default frame interval stays between
- * the boundaries.
- */
+ /* Clamp the default frame interval to the boundaries. */
n -= frame->bFrameIntervalType ? 1 : 2;
frame->dwDefaultFrameInterval =
clamp(frame->dwDefaultFrameInterval,
frame->dwFrameInterval[0],
frame->dwFrameInterval[n]);
+ /*
+ * Some devices report frame intervals that are not functional.
+ * If the corresponding quirk is set, restrict operation to the
+ * first interval only.
+ */
if (dev->quirks & UVC_QUIRK_RESTRICT_FRAME_RATE) {
frame->bFrameIntervalType = 1;
frame->dwFrameInterval[0] =