Re: [PATCH v2 18/31] gp8psk: don't do DMA on stack

From	Mauro Carvalho Chehab <mchehab@s-opensource.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v2 18/31] gp8psk: don't do DMA on stack
Date	2016-11-07 14:00 +0100
Message-ID	<sARGT-3e5-33@gated-at.bofh.it> (permalink)
References	<sr2k9-5sy-3@gated-at.bofh.it> <sr2kb-5sy-45@gated-at.bofh.it> <sABVn-1zd-15@gated-at.bofh.it> <sAQro-2rT-3@gated-at.bofh.it>
Organization	Samsung

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Em Mon, 7 Nov 2016 12:29:47 +0100
Johannes Stezenbach <js@linuxtv.org> escreveu:

> On Sun, Nov 06, 2016 at 11:51:14AM -0800, VDR User wrote:
> > I applied this patch to the 4.8.4 kernel driver (that I'm currently
> > running) and it caused nothing but "frontend 0/0 timed out while
> > tuning". Is there another patch that should be used in conjunction
> > with this? If not, this patch breaks the gp8psk driver.
> > 
> > Thanks.  
> 
> Thanks for testing.  "If it's not tested it's broken"...
> 
> > On Tue, Oct 11, 2016 at 3:09 AM, Mauro Carvalho Chehab
> > <mchehab@s-opensource.com> wrote:  
> 
> > > index 5d0384dd45b5..fa215ad37f7b 100644
> > > --- a/drivers/media/usb/dvb-usb/gp8psk.c
> > > +++ b/drivers/media/usb/dvb-usb/gp8psk.c  
> 
> > >  int gp8psk_usb_in_op(struct dvb_usb_device *d, u8 req, u16 value, u16 index, u8 *b, int blen)
> > >  {
> > > +       struct gp8psk_state *st = d->priv;
> > >         int ret = 0,try = 0;
> > >
> > >         if ((ret = mutex_lock_interruptible(&d->usb_mutex)))
> > >                 return ret;
> > >
> > >         while (ret >= 0 && ret != blen && try < 3) {
> > > +               memcpy(st->data, b, blen);
> > >                 ret = usb_control_msg(d->udev,
> > >                         usb_rcvctrlpipe(d->udev,0),
> > >                         req,
> > >                         USB_TYPE_VENDOR | USB_DIR_IN,
> > > -                       value,index,b,blen,
> > > +                       value, index, st->data, blen,
> > >                         2000);  
> 
> I guess for usb_in the memcpy should be after the usb_control_msg
> and from st->data to b.

Yes, this should fix the issue. Just sent a patch with Johannes
suggestion. Please test.

Regards,
Mauro

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Re: [PATCH v2 18/31] gp8psk: don't do DMA on stack VDR User <user.vdr@gmail.com> - 2016-11-06 21:10 +0100
  Re: [PATCH v2 18/31] gp8psk: don't do DMA on stack Johannes Stezenbach <js@linuxtv.org> - 2016-11-07 12:40 +0100
    Re: [PATCH v2 18/31] gp8psk: don't do DMA on stack Mauro Carvalho Chehab <mchehab@s-opensource.com> - 2016-11-07 14:00 +0100

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