Am 31.10.2012 12:57, schrieb Ezequiel Garcia: > On Tue, Oct 30, 2012 at 10:39 PM, Benny Amorsen <benny+usenet@xxxxxxxxxx> wrote: >> Frank Schäfer <fschaefer.oss@xxxxxxxxxxxxxx> writes: >> >>> This patch series adds support for USB bulk transfers to the em28xx driver. >> I tried these patches on my Raspberry Pi, 3.6.1 kernel, Nanostick 290e >> >> options em28xx prefer_bulk=1 core_debug=1 usb_debug=1 >> options em28xx_dvb debug=1 >> >> [ 5.469510] em28xx: New device PCTV Systems PCTV 290e @ 480 Mbps (2013:024f, interface 0, class 0) >> [ 5.890637] em28xx: DVB interface 0 found >> [ 6.025292] em28xx #0: chip ID is em28174 >> [ 6.515383] em28xx #0: Identified as PCTV nanoStick T2 290e (card=78) >> [ 6.567066] em28xx #0: v4l2 driver version 0.1.3 >> [ 6.614720] em28xx #0 em28xx_set_alternate :minimum isoc packet size: 2888 (alt=0) >> [ 6.663064] em28xx #0 em28xx_set_alternate :setting alternate 0 with wMaxPacketSize=0 >> [ 6.715934] em28xx #0 em28xx_accumulator_set :em28xx Scale: (1,1)-(179,143) >> [ 6.765694] em28xx #0 em28xx_capture_area_set :em28xx Area Set: (180,144) >> [ 6.793060] em28xx #0: V4L2 video device registered as video0 >> [ 6.808200] em28xx #0 em28xx_alloc_urbs :em28xx: called em28xx_alloc_isoc in mode 2 >> [ 6.819456] em28xx #0: no endpoint for DVB mode and transfer type 1 >> [ 6.829283] em28xx: Failed to pre-allocate USB transfer buffers for DVB. >> [ 6.839454] em28xx: probe of 1-1.3.1:1.0 failed with error -22 >> [ 6.852511] usbcore: registered new interface driver em28xx >> [ 7.255738] em28xx #0 em28xx_accumulator_set :em28xx Scale: (1,1)-(179,143) >> [ 7.291575] em28xx #0 em28xx_capture_area_set :em28xx Area Set: (180,144) >> [ 7.326200] em28xx #0 em28xx_uninit_usb_xfer :em28xx: called em28xx_uninit_usb_xfer in mode 1 >> >> Is the Nanostick 290e just fundamentally incompatible with bulk >> transfers, or is there hope yet? >> >> It works great with isochronous transfers on my PC and the Fedora >> kernel, but the Raspberry USB host blows up when trying to do >> isochronous mode. >> >> > Isn't this completely OT? > > Anyway, RPI has known issues regarding USB bandwidth. > > See here > > https://github.com/ezequielgarcia/stk1160-standalone/issues/8 > https://github.com/ezequielgarcia/stk1160-standalone/issues/2 > http://www.raspberrypi.org/phpBB3/viewtopic.php?p=196918#p196918 For DVB, the em28xx always selects the alternate setting with the largest wMaxPacketSize. There is a module parameter 'alt' to select it manually for experiments, but the current code unfortunately applies it for analog capturing only. :( Hope this helps, Frank > Regards, > > Ezequiel -- 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
