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    SubjectRe: 2.6.33 bugs (USBFS, Intel graphic)
    From
    On Sat, Feb 27, 2010 at 6:26 AM, Greg KH <greg@kroah.com> wrote:
    > On Fri, Feb 26, 2010 at 09:17:37PM -0800, Greg KH wrote:
    >> On Sat, Feb 27, 2010 at 05:34:27AM +0100, Markus Rechberger wrote:
    >> > On Sat, Feb 27, 2010 at 5:29 AM, Linus Torvalds
    >> > <torvalds@linux-foundation.org> wrote:
    >> > >
    >> > >
    >> > > On Fri, 26 Feb 2010, Greg KH wrote:
    >> > >>
    >> > >> Yes, and that patch didn't touch the iso frames. ?That happens later on
    >> > >> in the functions that were modified. ?The patch should not have had any
    >> > >> affect on iso transfers. ?Unless I'm missing something?
    >> > >
    >> > > Hmm. What seems to happen is that for an isochronous transfer, the buffer
    >> > > is split for each microframe. No?
    >> > >
    >> >
    >> > exactly. and each microframe has its own buffer length identifier.
    >> >
    >> > the current behaviour breaks VMware, QEMU and virtualbox .. probably
    >> > other things too.
    >> >
    >> >
    >> > > So the total length may be in 'urb->actual_length', but the actual data in
    >> > > the buffer may not be contiguous, because it's created from multiple
    >> > > smaller frames, some of which might not be full length?
    >> > >
    >> >
    >> > yes, it's only contiguous for BULK.
    >> >
    >> > > I dunno. That would explain the problem - actual_length is correct, but
    >> > > the 'copy_to_user()' still doesn't copy all the data, because it's
    >> > > fragmented.
    >> > >
    >> >
    >> > no you got it, but your patch does not work. The best way would be to
    >> > revert it if someone wants to speed up BULK it should go down another
    >> > path, leaving the old working implementation untouched.
    >>
    >> Hm, so it's back to the original idea of just doing a kzalloc of the
    >> initial buffer, that should solve the problem that Marcus found.
    >>
    >> I'll go dig that back up and if you could test it, that would be most
    >> appreciated.
    >
    > Here, can you try this on top of everything?
    >

    just tested it, everything's back to normal again now!

    thanks,
    Markus

    > thanks,
    >
    > greg k-h
    >
    >
    > diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
    > index a678186..252d3b4 100644
    > --- a/drivers/usb/core/devio.c
    > +++ b/drivers/usb/core/devio.c
    > @@ -1168,7 +1168,7 @@ static int proc_do_submiturb(struct dev_state *ps, struct usbdevfs_urb *uurb,
    >                return -ENOMEM;
    >        }
    >        if (uurb->buffer_length > 0) {
    > -               as->urb->transfer_buffer = kmalloc(uurb->buffer_length,
    > +               as->urb->transfer_buffer = kzalloc(uurb->buffer_length,
    >                                GFP_KERNEL);
    >                if (!as->urb->transfer_buffer) {
    >                        kfree(isopkt);
    > @@ -1312,9 +1312,9 @@ static int processcompl(struct async *as, void __user * __user *arg)
    >        void __user *addr = as->userurb;
    >        unsigned int i;
    >
    > -       if (as->userbuffer && urb->actual_length)
    > +       if (as->userbuffer)
    >                if (copy_to_user(as->userbuffer, urb->transfer_buffer,
    > -                                urb->actual_length))
    > +                                urb->transfer_buffer_length))
    >                        goto err_out;
    >        if (put_user(as->status, &userurb->status))
    >                goto err_out;
    > @@ -1480,9 +1480,9 @@ static int processcompl_compat(struct async *as, void __user * __user *arg)
    >        void __user *addr = as->userurb;
    >        unsigned int i;
    >
    > -       if (as->userbuffer && urb->actual_length)
    > +       if (as->userbuffer)
    >                if (copy_to_user(as->userbuffer, urb->transfer_buffer,
    > -                                urb->actual_length))
    > +                                urb->transfer_buffer_length))
    >                        return -EFAULT;
    >        if (put_user(as->status, &userurb->status))
    >                return -EFAULT;
    >
    --
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