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From: Michal Pecio <michal.pecio@gmail.com>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: linux-media@vger.kernel.org
Subject: [PATCH] media: uvcvideo: fix the bandwdith quirk on USB 3.x
Date: Sun, 14 Apr 2024 19:00:40 +0200	[thread overview]
Message-ID: <20240414190040.2255a0bc@foxbook> (raw)

The bandwidth fixup quirk doesn't know that SuperSpeed exists and has
the same 8 service intervals per millisecond as High Speed, hence its
calculations are wrong.

Assume that all speeds from HS up use 8 intervals per millisecond.

No further changes are needed, updated code has been confirmed to work
with all speeds from FS to SS.

Signed-off-by: Michal Pecio <michal.pecio@gmail.com>
---
 drivers/media/usb/uvc/uvc_video.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index 28dde08ec6c5..4b86bef06a52 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -214,13 +214,13 @@ static void uvc_fixup_video_ctrl(struct uvc_streaming *stream,
 		 * 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).
+		 * high- and super-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 (stream->dev->udev->speed == USB_SPEED_HIGH)
+		if (stream->dev->udev->speed >= USB_SPEED_HIGH)
 			bandwidth /= 8;
 		bandwidth += 12;
 
-- 
2.43.0


             reply	other threads:[~2024-04-14 17:00 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-14 17:00 Michal Pecio [this message]
2024-04-15 19:46 ` [PATCH] media: uvcvideo: fix the bandwdith quirk on USB 3.x Ricardo Ribalda
2024-06-16 23:26 ` Laurent Pinchart

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