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

From: Johannes Stezenbach
Date: Mon Nov 07 2016 - 06:30:15 EST


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@xxxxxxxxxxxxxxxx> 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.

Johannes