Hi Laurent,
Sorry about the delay, I forgot about this. :/
On Mon, Oct 30, 2017 at 09:59:34PM +0100, Laurent Caumont wrote:
> Hi Sean,
>
> I found the problem. The read buffer needs to be allocated with kmalloc too.
>
> int dibusb_read_eeprom_byte(struct dvb_usb_device *d, u8 offs, u8 *val)
> {
> u8 *wbuf;
> u8 *rbuf;
> int rc;
>
> rbuf = kmalloc(1, GFP_KERNEL);
> if (!rbuf)
> return -ENOMEM;
>
> wbuf = kmalloc(1, GFP_KERNEL);
> if (!wbuf)
> return -ENOMEM;
>
> *wbuf = offs;
>
> rc = dibusb_i2c_msg(d, 0x50, wbuf, 1, rbuf, 1);
> kfree(wbuf);
> *val = *rbuf;
> kfree(rbuf);
>
> return rc;
> }
Looks good. Would you mind sending either a Signed-off-by: or submit it
as a patch?
Thanks
Sean
>
> It works now.
> Please update the code in the main branch for futur versions.
> Thanks.
> Regards,
> Laurent
>
> 2017-10-29 20:31 GMT+01:00 Sean Young <sean@xxxxxxxx>:
> > On Sun, Oct 29, 2017 at 06:54:28PM +0100, Laurent Caumont wrote:
> >> Hi Sean,
> >>
> >> I recompiled the modules by following the
> >> https://www.linuxtv.org/wiki/index.php/How_to_Obtain,_Build_and_Install_V4L-DVB_Device_Drivers
> >> page and applied the patch.
> >> But I still have problems (see below). It doesn't seem to be the same callstack.
> >> Is it the right way to get the fix ?
> >
> > Yes, it's the right way to get the fix. However, you've hit a new problem
> > of a similar making. Please can you try with this patch as well:
> >
> > Thanks
> > Sean
> > ---
> > From 84efb0bf72ae5d9183f25d69d95fb9ad9b9bc644 Mon Sep 17 00:00:00 2001
> > From: Sean Young <sean@xxxxxxxx>
> > Date: Sun, 29 Oct 2017 19:28:32 +0000
> > Subject: [PATCH] media: dibusb: don't do DMA on stack
> >
> > The USB control messages require DMA to work. We cannot pass
> > a stack-allocated buffer, as it is not warranted that the
> > stack would be into a DMA enabled area.
> >
> > Signed-off-by: Sean Young <sean@xxxxxxxx>
> > ---
> > drivers/media/usb/dvb-usb/dibusb-common.c | 14 ++++++++++++--
> > 1 file changed, 12 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/media/usb/dvb-usb/dibusb-common.c b/drivers/media/usb/dvb-usb/dibusb-common.c
> > index 8207e6900656..18c6e454b1b7 100644
> > --- a/drivers/media/usb/dvb-usb/dibusb-common.c
> > +++ b/drivers/media/usb/dvb-usb/dibusb-common.c
> > @@ -223,8 +223,18 @@ EXPORT_SYMBOL(dibusb_i2c_algo);
> >
> > int dibusb_read_eeprom_byte(struct dvb_usb_device *d, u8 offs, u8 *val)
> > {
> > - u8 wbuf[1] = { offs };
> > - return dibusb_i2c_msg(d, 0x50, wbuf, 1, val, 1);
> > + u8 *wbuf;
> > + int rc;
> > +
> > + wbuf = kmalloc(1, GFP_KERNEL);
> > + if (!wbuf)
> > + return -ENOMEM;
> > +
> > + *wbuf = offs;
> > + rc = dibusb_i2c_msg(d, 0x50, wbuf, 1, val, 1);
> > + kfree(wbuf);
> > +
> > + return rc;
> > }
> > EXPORT_SYMBOL(dibusb_read_eeprom_byte);
> >
> > --
> > 2.13.6
> >
