On Wed, 19 Jan 2011, Andy Walls wrote: > On Wed, 2011-01-19 at 13:40 +0100, Jean Delvare wrote: > > On Wed, 19 Jan 2011 07:21:58 -0500, Andy Walls wrote: > > > For debugging, you might want to hack in a probe of address 0x70 for > > > your HVR-1950, to ensure the Tx side responds in the bridge driver. > > > > ... keeping in mind that the Z8 doesn't seem to like quick writes, so > > short reads should be used for probing purpose. > > > > Noted. Thanks. > > Actually, I think that might be due to the controller in the USB > connected devices (hdpvr and pvrusb2). The PCI connected devices, like > cx18 cards, don't have a problem with the Z8, the default I2C probe > method, and i2c-algo-bit. > (A good example of why only bridge drivers should do any required > probing.) > > > Looking at the code in pvrusb2, it appears to already use a 0 length > read for a probe: > > http://git.linuxtv.org/media_tree.git?a=blob;f=drivers/media/video/pvrusb2/pvrusb2-i2c-core.c;h=ccc884948f34b385563ccbf548c5f80b33cd4f08;hb=refs/heads/staging/for_2.6.38-rc1#l542 Yes but that function is used in two places: (1) If a bus scan is performed during initialization (normally it isn't), and (2) it is called once ONLY for a 24xxx device (targeting 0x71) in order to determine if it is dealing with the MCE variant. -Mike -- Mike Isely isely @ isely (dot) net PGP: 03 54 43 4D 75 E5 CC 92 71 16 01 E2 B5 F5 C1 E8 -- 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
