Em 28-07-2011 08:42, Kirill Smelkov escreveu: > On Wed, Jul 27, 2011 at 09:42:08PM +0200, Mauro Carvalho Chehab wrote: >> This is an automatic generated email to let you know that the following patch were queued at the >> http://git.linuxtv.org/media_tree.git tree: >> >> Subject: [media] uvcvideo: Add FIX_BANDWIDTH quirk to HP Webcam on HP Mini 5103 netbook >> Author: Kirill Smelkov <kirr@xxxxxxxxxx> >> Date: Fri Jul 22 11:47:22 2011 -0300 > > Thanks > > >> 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@xxxxxxxxxxxxxxxx> >> Signed-off-by: Kirill Smelkov <kirr@xxxxxxxxxx> >> Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx> > > > May I ask, why you removed the reference to cc62a7eb? Original patch > description contained the following paragraph just before sob > > Now with tweaked ehci-hcd to allow up to 90% isoc bandwidth (cc62a7eb > "USB: EHCI: Allow users to override 80% max periodic bandwidth") I can > capture two video sources -- PAL 720x576 YUV422 @25fps + NTSC 640x480 > YUV422 @30fps simultaneously. Hooray! > > > which was removed on applying. For a few reasons: 1) I was not sure if the changeset reference was not changed when merged upstream, and I was too lazy^Wbusy to double check ;) 2) Reducing the amount of bandwidth used is good, even without trying to use two webcams; 3) The bandwidth override patch is independent of this one. Regards, Mauro -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
