2009-10-17 20:46:53

by Stefan Richter

Subject: [PATCH] firedtv: fix regression: tuning fails due to bogus error return

Since 2.6.32(-rc1), DVB core checks the return value of
dvb_frontend_ops.set_frontend. Now it becomes apparent that firedtv
always returned a bogus value from its set_frontend method.

Signed-off-by: Stefan Richter <[email protected]>
---
drivers/media/dvb/firewire/firedtv-avc.c | 7 +++++--
drivers/media/dvb/firewire/firedtv-fe.c | 8 +-------
2 files changed, 6 insertions(+), 9 deletions(-)

Index: linux-2.6.32-rc5/drivers/media/dvb/firewire/firedtv-avc.c
===================================================================
--- linux-2.6.32-rc5.orig/drivers/media/dvb/firewire/firedtv-avc.c
+++ linux-2.6.32-rc5/drivers/media/dvb/firewire/firedtv-avc.c
@@ -573,8 +573,11 @@ int avc_tuner_dsd(struct firedtv *fdtv,

msleep(500);
#if 0
- /* FIXME: */
- /* u8 *status was an out-parameter of avc_tuner_dsd, unused by caller */
+ /*
+ * FIXME:
+ * u8 *status was an out-parameter of avc_tuner_dsd, unused by caller
+ * Check for AVC_RESPONSE_ACCEPTED here instead?
+ */
if (status)
*status = r->operand[2];
#endif
Index: linux-2.6.32-rc5/drivers/media/dvb/firewire/firedtv-fe.c
===================================================================
--- linux-2.6.32-rc5.orig/drivers/media/dvb/firewire/firedtv-fe.c
+++ linux-2.6.32-rc5/drivers/media/dvb/firewire/firedtv-fe.c
@@ -141,18 +141,12 @@ static int fdtv_read_uncorrected_blocks(
return -EOPNOTSUPP;
}

-#define ACCEPTED 0x9
-
static int fdtv_set_frontend(struct dvb_frontend *fe,
struct dvb_frontend_parameters *params)
{
struct firedtv *fdtv = fe->sec_priv;

- /* FIXME: avc_tuner_dsd never returns ACCEPTED. Check status? */
- if (avc_tuner_dsd(fdtv, params) != ACCEPTED)
- return -EINVAL;
- else
- return 0; /* not sure of this... */
+ return avc_tuner_dsd(fdtv, params);
}

static int fdtv_get_frontend(struct dvb_frontend *fe,

--
Stefan Richter
-=====-==--= =-=- =---=
http://arcgraph.de/sr/

2009-11-13 10:10:06

by Stefan Richter

Subject: Re: [PATCH] firedtv: fix regression: tuning fails due to bogus error return

Stefan Richter wrote on 2009-10-17:
> Since 2.6.32(-rc1), DVB core checks the return value of
> dvb_frontend_ops.set_frontend. Now it becomes apparent that firedtv
> always returned a bogus value from its set_frontend method.
>
> Signed-off-by: Stefan Richter <[email protected]>

Hi Mauro,

when you committed this, you added "CC: [email protected]". This is not
necessary, 2.6.32-rc1 is the first kernel version with the regression
(see changelog).

Well, OK, the patch would become necessary in -stable if somebody was to
put the new set_frontend return code check in dvb core into -stable. But
I hope nobody is going to do that; it'd be a bad idea.

Furthermore...

> ---
> drivers/media/dvb/firewire/firedtv-avc.c | 7 +++++--
> drivers/media/dvb/firewire/firedtv-fe.c | 8 +-------
> 2 files changed, 6 insertions(+), 9 deletions(-)
>
> Index: linux-2.6.32-rc5/drivers/media/dvb/firewire/firedtv-avc.c
> ===================================================================
> --- linux-2.6.32-rc5.orig/drivers/media/dvb/firewire/firedtv-avc.c
> +++ linux-2.6.32-rc5/drivers/media/dvb/firewire/firedtv-avc.c
> @@ -573,8 +573,11 @@ int avc_tuner_dsd(struct firedtv *fdtv,
>
> msleep(500);
> #if 0
> - /* FIXME: */
> - /* u8 *status was an out-parameter of avc_tuner_dsd, unused by caller */
> + /*
> + * FIXME:
> + * u8 *status was an out-parameter of avc_tuner_dsd, unused by caller
> + * Check for AVC_RESPONSE_ACCEPTED here instead?
> + */
> if (status)
> *status = r->operand[2];
> #endif

...the firedtv-avc.c part of the patch vanished when you committed it. I
guess this was accident, not deliberate --- otherwise a note in the
changelog below of my Signed-off-by would have been appreciated.

I will resubmit this missing comment change or a variation of it or even
a fix of the FIXME sometime in the future.

> Index: linux-2.6.32-rc5/drivers/media/dvb/firewire/firedtv-fe.c
> ===================================================================
> --- linux-2.6.32-rc5.orig/drivers/media/dvb/firewire/firedtv-fe.c
> +++ linux-2.6.32-rc5/drivers/media/dvb/firewire/firedtv-fe.c
> @@ -141,18 +141,12 @@ static int fdtv_read_uncorrected_blocks(
> return -EOPNOTSUPP;
> }
>
> -#define ACCEPTED 0x9
> -
> static int fdtv_set_frontend(struct dvb_frontend *fe,
> struct dvb_frontend_parameters *params)
> {
> struct firedtv *fdtv = fe->sec_priv;
>
> - /* FIXME: avc_tuner_dsd never returns ACCEPTED. Check status? */
> - if (avc_tuner_dsd(fdtv, params) != ACCEPTED)
> - return -EINVAL;
> - else
> - return 0; /* not sure of this... */
> + return avc_tuner_dsd(fdtv, params);
> }
>
> static int fdtv_get_frontend(struct dvb_frontend *fe,
>

--
Stefan Richter
-=====-==--= =-== -==-=
http://arcgraph.de/sr/

2009-11-13 10:20:41

by Stefan Richter

Subject: Re: [PATCH] firedtv: fix regression: tuning fails due to bogus error return

Stefan Richter wrote:
> ...the firedtv-avc.c part of the patch vanished when you committed it.

It was still there in the linuxtv-commits message of the respective
Mercurial commit, BTW. Something wrong with the hg to git workflow?
--
Stefan Richter
-=====-==--= =-== -==-=
http://arcgraph.de/sr/