[CC Takashi] On Mon, Feb 01, 2010 at 05:29:14PM +0000, Catalin Marinas wrote: > On Fri, 2010-01-29 at 18:54 +0000, Matthew Dharm wrote: > > HOWEVER, I firmly believe that the cache-management functions belong with > > the driver that actually talks to the low-level hardware, as that's the > > only place where you can be 100% certain of what cache operations are > > needed. After all, I think someone is working on a USB-over-IP transport, > > and trying to manage cache at the usb-storage level in that scenario is > > just silly. > > > > So, let's put this in the HCD drivers and be done with it. > > The patch below is what fixes the I-D cache incoherency issues on ARM. I > don't particularly like the solution but it seems to be the only one > available. Thanks very much for working on this amazingly large problem! I took some time to add your patch to ehci-q.c / ohci-q.c (for my *hci-ssb.c ASUS WL-500gP v2), on my now _heavily_ patched-up 2.6.31.9, but _UNFORTUNATELY_ it kept locking up the same way as always when stopping playback despite being damn sure this time that this patch could have the potential to finally fix it ;) (I had to replace memory.h with page.h on my arch though, to fix the build) This is on MIPSEL (not one of my many ARM devices, unfortunately ;), with usb-audio, and the madplay process crashes in __bzero(), which strongly indicates cache coherency issues (other subsequent backtraces have lots of mmap and vma listed, see also my "snd_usb_audio OOPS on MIPSEL - is that the mmap issue?"). Next thing I'll do is fire up gdb and get a good backtrace of the __bzero() address to find out which page handling in mpd exactly is hampered with crashes. This is now ~ the third patch that I applied on-the-go and that didn't help, so it's probably time to do some earnest analysis on what's really going on locally. Note that usb-storage itself does work on this platform though. Rather annoying to be so close (sound works) yet so far away, especially after all that USB host trouble I already had. Thanks a lot again, Andreas Mohr -- 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
