2010/11/25 Anand Gadiyar <gadiyar@xxxxxx>: > Felipe Balbi wrote: >> Hi, >> >> On Thu, Nov 25, 2010 at 04:54:05PM +0800, Bob Liu wrote: >> >>> The only work around is to config the receive FIFO into single > buffer >> >>> mode. >> >> >> >> And how to do that ? >> >> >> > >> >It's used to by "USB: musb: disable double buffering for older RTL >> >versions" >> >>http://git.kernel.org/?p=linux/kernel/git/next/linux-next.git;a=commitdif > f;h=9f445cb29918dc488b7a9a92ef018599cce33df7 >> >> yeah, but that breaks other stuff high bandwidth eps, so we need a >> better way to "disable double buffering". >> > > Here's how I understand the problem. > > Blackfin has a statically configured fifo allocation - with no > possibility to change it. The IP uses double buffering by default > if a FIFO is allocated space enough to hold 2*maxp (which is the > case for at least some of the endpoints). > > The only way to make the IP use single buffering is to tell the > IP that the maxp is different. > > This is an anomaly only in the blackfin - I don't see any way to > work around this (for lack of information), than what has been > implemented in the patch that already got merged. Yes, I agree. > > However, that code should be made to execute only on blackfin > and not on other platforms - so that the others are not broken > by that change. Even in blackfin platform, the code may break some function, especially for full speed device, which was explained a lot in the previous discussion: http://marc.info/?t=128576512000002&r=1&w=2 > > Is this a fair summary? -- Lei Ming -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
