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. 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. Is this a fair summary? - Anand -- 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
