From 949d9264589b759df66d40d497d14ecc49681b3a Mon Sep 17 00:00:00 2001
From: Kirill Smelkov <kirr@mns.spb.ru>
Date: Fri, 22 Jul 2011 11:47:22 -0300
Subject: [PATCH] [media] uvcvideo: Add FIX_BANDWIDTH quirk to HP Webcam on HP
 Mini 5103 netbook

The camera there identifies itself as being manufactured by Cheng Uei
Precision Industry Co., Ltd (Foxlink), and product is titled as "HP
Webcam [2 MP Fixed]".

I was trying to get 2 USB video capture devices to work simultaneously,
and noticed that the above mentioned webcam always requires packet size
= 3072 bytes per micro frame (~= 23.4 MB/s isoc bandwidth), which is far
more than enough to get standard NTSC 640x480x2x30 = ~17.6 MB/s isoc
bandwidth.

As there are alt interfaces with smaller MxPS

    T:  Bus=01 Lev=01 Prnt=01 Port=03 Cnt=01 Dev#=  2 Spd=480  MxCh= 0
    D:  Ver= 2.00 Cls=ef(misc ) Sub=02 Prot=01 MxPS=64 #Cfgs=  1
    P:  Vendor=05c8 ProdID=0403 Rev= 1.06
    S:  Manufacturer=Foxlink
    S:  Product=HP Webcam [2 MP Fixed]
    S:  SerialNumber=200909240102
    C:* #Ifs= 2 Cfg#= 1 Atr=80 MxPwr=500mA
    A:  FirstIf#= 0 IfCount= 2 Cls=0e(video) Sub=03 Prot=00
    I:* If#= 0 Alt= 0 #EPs= 1 Cls=0e(video) Sub=01 Prot=00 Driver=uvcvideo
    E:  Ad=83(I) Atr=03(Int.) MxPS=  16 Ivl=4ms
    I:* If#= 1 Alt= 0 #EPs= 0 Cls=0e(video) Sub=02 Prot=00 Driver=uvcvideo
    I:  If#= 1 Alt= 1 #EPs= 1 Cls=0e(video) Sub=02 Prot=00 Driver=uvcvideo
    E:  Ad=81(I) Atr=05(Isoc) MxPS= 128 Ivl=125us
    I:  If#= 1 Alt= 2 #EPs= 1 Cls=0e(video) Sub=02 Prot=00 Driver=uvcvideo
    E:  Ad=81(I) Atr=05(Isoc) MxPS= 512 Ivl=125us
    I:  If#= 1 Alt= 3 #EPs= 1 Cls=0e(video) Sub=02 Prot=00 Driver=uvcvideo
    E:  Ad=81(I) Atr=05(Isoc) MxPS=1024 Ivl=125us
    I:  If#= 1 Alt= 4 #EPs= 1 Cls=0e(video) Sub=02 Prot=00 Driver=uvcvideo
    E:  Ad=81(I) Atr=05(Isoc) MxPS=1536 Ivl=125us
    I:  If#= 1 Alt= 5 #EPs= 1 Cls=0e(video) Sub=02 Prot=00 Driver=uvcvideo
    E:  Ad=81(I) Atr=05(Isoc) MxPS=2048 Ivl=125us
    I:  If#= 1 Alt= 6 #EPs= 1 Cls=0e(video) Sub=02 Prot=00 Driver=uvcvideo
    E:  Ad=81(I) Atr=05(Isoc) MxPS=2688 Ivl=125us
    I:  If#= 1 Alt= 7 #EPs= 1 Cls=0e(video) Sub=02 Prot=00 Driver=uvcvideo
    E:  Ad=81(I) Atr=05(Isoc) MxPS=3072 Ivl=125us

UVC_QUIRK_FIX_BANDWIDTH helps here and NTSC video can be served with
MxPS=2688 i.e. 20.5 MB/s isoc bandwidth.

In terms of microframe time allocation, before the quirk NTSC video
required 60 usecs / microframe and 53 usecs / microframe after.

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
---
 drivers/media/video/uvc/uvc_driver.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/media/video/uvc/uvc_driver.c b/drivers/media/video/uvc/uvc_driver.c
index 749c72222665..d29f9c2d0854 100644
--- a/drivers/media/video/uvc/uvc_driver.c
+++ b/drivers/media/video/uvc/uvc_driver.c
@@ -2131,6 +2131,15 @@ static struct usb_device_id uvc_ids[] = {
 	  .bInterfaceProtocol	= 0,
 	  .driver_info 		= UVC_QUIRK_PROBE_MINMAX
 				| UVC_QUIRK_BUILTIN_ISIGHT },
+	/* Foxlink ("HP Webcam" on HP Mini 5103) */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x05c8,
+	  .idProduct		= 0x0403,
+	  .bInterfaceClass	= USB_CLASS_VIDEO,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0,
+	  .driver_info		= UVC_QUIRK_FIX_BANDWIDTH },
 	/* Genesys Logic USB 2.0 PC Camera */
 	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
 				| USB_DEVICE_ID_MATCH_INT_INFO,
-- 
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