Date: Wed, 23 Apr 2008 14:03:27 -0700 From: Sam Leffler <sam@freebsd.org> To: Marius Strobl <marius@alchemy.franken.de> Cc: cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/dev/usb ehci.c ohci.c Message-ID: <480FA41F.20407@freebsd.org> In-Reply-To: <20080423205943.GG99566@alchemy.franken.de> References: <200803201619.m2KGJQr7033985@repoman.freebsd.org> <20080412193358.GA44768@alchemy.franken.de> <20080423203622.GA66545@alchemy.franken.de> <480F9F8B.5050209@freebsd.org> <20080423205943.GG99566@alchemy.franken.de>
next in thread | previous in thread | raw e-mail | index | archive | help
Marius Strobl wrote:
> On Wed, Apr 23, 2008 at 01:43:55PM -0700, Sam Leffler wrote:
>
>> Marius Strobl wrote:
>>
>>> On Sat, Apr 12, 2008 at 09:33:58PM +0200, Marius Strobl wrote:
>>>
>>>
>>>> On Thu, Mar 20, 2008 at 04:19:26PM +0000, Sam Leffler wrote:
>>>>
>>>>
>>>>> sam 2008-03-20 16:19:25 UTC
>>>>>
>>>>> FreeBSD src repository
>>>>>
>>>>> Modified files:
>>>>> sys/dev/usb ehci.c ohci.c
>>>>> Log:
>>>>> Workaround design botch in usb: blindly mixing bus_dma with PIO does
>>>>> not
>>>>> work on architectures with a write-back cache as the PIO writes end up
>>>>> in the cache which the sync(BUS_DMASYNC_POSTREAD) in
>>>>> usb_transfer_complete
>>>>> then discards; compensate in the xfer methods that do PIO by pushing
>>>>> the
>>>>> writes out of the cache before usb_transfer_complete is called.
>>>>>
>>>>> This fixes USB on xscale and likely other places.
>>>>>
>>>>> Sponsored by: hobnob
>>>>> Reviewed by: cognet, imp
>>>>> MFC after: 1 month
>>>>>
>>>>> Revision Changes Path
>>>>> 1.62 +16 -0 src/sys/dev/usb/ehci.c
>>>>> 1.171 +16 -0 src/sys/dev/usb/ohci.c
>>>>>
>>>>>
>>>> This causes a crash during boot on sparc64. Looks like map is still
>>>> NULL at that point.
>>>>
>>>>
>>>>
>>> Are you ok with the change below or would that also prevent
>>> your kludge from taking effect?
>>>
>>> Marius
>>>
>>> Index: ehci.c
>>> ===================================================================
>>> RCS file: /usr/data/bsd/cvs/fbsd/src/sys/dev/usb/ehci.c,v
>>> retrieving revision 1.62
>>> diff -u -r1.62 ehci.c
>>> --- ehci.c 20 Mar 2008 16:19:25 -0000 1.62
>>> +++ ehci.c 23 Apr 2008 20:23:58 -0000
>>> @@ -664,6 +664,8 @@
>>> usbd_pipe_handle pipe = xfer->pipe;
>>> bus_dma_tag_t tag = pipe->device->bus->buffer_dmatag;
>>> struct usb_dma_mapping *dmap = &xfer->dmamap;
>>> + if (dmap->map == NULL)
>>> + return;
>>> bus_dmamap_sync(tag, dmap->map, BUS_DMASYNC_PREWRITE);
>>> }
>>>
>>> Index: ohci.c
>>> ===================================================================
>>> RCS file: /usr/data/bsd/cvs/fbsd/src/sys/dev/usb/ohci.c,v
>>> retrieving revision 1.171
>>> diff -u -r1.171 ohci.c
>>> --- ohci.c 20 Mar 2008 16:19:25 -0000 1.171
>>> +++ ohci.c 21 Apr 2008 19:13:54 -0000
>>> @@ -1571,6 +1571,8 @@
>>> usbd_pipe_handle pipe = xfer->pipe;
>>> bus_dma_tag_t tag = pipe->device->bus->buffer_dmatag;
>>> struct usb_dma_mapping *dmap = &xfer->dmamap;
>>> + if (dmap->map == NULL)
>>> + return;
>>> bus_dmamap_sync(tag, dmap->map, BUS_DMASYNC_PREWRITE);
>>> }
>>>
>>>
>>>
>>>
>>>
>> You have not identified why you don't have a dma map. I don't have a
>> way to diagnose your problem and so far as I know no other platform had
>> an issue w/ the change. I suggest you figure out why your map is not
>> setup instead of adding a hack.
>>
>>
>
> It's because the usb(4) code doesn't create DMA maps for
> zero-length transfers, see usbd_transfer(). In the case of
> the backtrace I posted not for usbd_set_address(), which
> does USETW(req.wLength, 0) so later on size is 0 in
> usbd_transfer() hence no DMA map. I don't know why your
> hack doesn't also crash other platforms.
>
Thanks for explaining, I will look. Please hold off for a bit.
Sam
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?480FA41F.20407>