[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>
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