> -----Original Message----- > From: Christoph Fritz [mailto:chf.fritz@xxxxxxxxxxxxxx] > Sent: 2012年5月9日 13:38 > To: Chen Peter-B29397; Chao Xie > Cc: Neil Zhang; Fabio Estevam; Li Yang-R58472; Felipe Balbi; Greg > Kroah-Hartman; linux-usb@xxxxxxxxxxxxxxx; linuxppc-dev@xxxxxxxxxxxxxxxx; > Hans J. Koch; Daniel Mack; Thomas Dahlmann; Nicolas Ferre; Eric Miao; > Russell King; Haojian Zhuang; Ben Dooks; Kukjin Kim; Sascha Hauer; > Oliver Neukum; Ido Shayevitz; Estevam Fabio-R49496 > Subject: Re: [RFC] [PATCH] usb: gadget: fix dtd dma confusion > > Hi Peter, > > thanks you for your help. > > On Wed, May 09, 2012 at 02:11:56AM +0000, Chen Peter-B29397 wrote: > > > > > > > > > > > > after a while of testing and searching I can come up with a patch > > > > that fixes g_ether <-> iperf for fsl_udc on ARM i.MX35. > > > > > > > > The sad part is that this kind of fix is already implemented for > > > > marvell mv_udc driver since last year but still _not_ in the ~15 > > > > other *udc.c drivers. > > > > > > > > It is a controller limitation (bug?) for chipidea controller when > using > > dtd list to handle multi-dtds situation. The controller will read > dtd's > > next pointer after this dtd's active bit has already been cleared. > > > > Freescale has an errata for this problem's description and solution. > > http://cache.freescale.com/files/dsp/doc/errata/IMX23CE.pdf > > See 2858 > > I'm hacking here an i.MX35 not an i.MX23. So I already had a look at > its > errata sheet > http://cache.freescale.com/files/dsp/doc/errata/IMX35CE.pdf > but didn't find a similar "limitation" as you now pointed out by errata > number 2858 for i.MX23. > > What about the fix for mv_udc, shouldn't they have a similar > "limitation"? How do you explain? > Or maybe someone from Marvell has an answer? > Yes, we encountered the same issue, and I have answered your question several hours ago. Please have a look. > > Thanks, > -- Christoph Best Regards, Neil Zhang ?韬{.n?????%??檩??w?{.n???{炳???骅w* jg????????G??⒏ ⒎?:+v???????? ????＂??????
