On Fri, Nov 14, 2014 at 10:39:15AM +0200, Mathias Nyman wrote: > On 13.11.2014 20:46, Felipe Balbi wrote: > > On Thu, Nov 13, 2014 at 12:31:28PM -0600, Felipe Balbi wrote: > >> Hi, > >> > >> (your mailing is un-wrapping emails, I always end up with pretty long > >> lines and have to rewrap them) > >> > >> On Thu, Nov 13, 2014 at 07:58:28PM +0200, Mathias Nyman wrote: > >>>> The algorithm described in the DVB tuner bug is clearly wrong, since > >>>> it doesn't move the dequeue pointer until usb_clear_halt() is > >>>> called, which is far too late. The right approach is to fix up the > >>>> dequeue pointer before giving back the URB (so there's no need to > >>>> save a "stopped TD" value). Otherwise there will be TDs in the > >>>> endpoint ring containing stale DMA pointers to buffers that have > >>>> already been unmapped. > >>> > >>> Thats right, I cleaned up the patch and removed resetting the endpoint > >>> from the .endpoint_reset() callback which was called as a result of > >>> usb_clear_halt(). Now we queue a reset endpoint and set dequeue > >>> pointer before giving back the URB. > >>> > >>> I still set a "stopped td" value, but could as well just pass it as > >>> function parameter. Actually I'll do that in later cleanup patch. > >>> > >>> Latest version of the patch is now in my tree in a reset-rework-v2 > >>> branch, with fixes comments and removed The brach includes the other > >>> dorbell ringing patch as well. both are on top of 3.18-rc4. > >>> > >>> I still need to test it before sending it further, the tree is here: > >>> > >>> git://git.kernel.org/pub/scm/linux/kernel/git/mnyman/xhci.git reset-rework-v2 > >> > >> I'll test this one. > > > > for both commits on that branch, you can add my: > > > > Tested-by: Felipe Balbi <balbi@xxxxxx> > > > > But please also add proper fixes and Cc: stable, so older kernels can > > use those. > > > > Thanks a lot for testing again. > > I'll CC stable and add your tested-by, but I still don't know exactly > which commit it Fixes. This might have been there since the early days > of xhci. git blame usually helps. Just look for code which was differentiating COMP_STALL and treating it differently. I know that at least v3.14 has the problem. -- balbi
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