Re: [PATCH] AVerTV MCE 116 Plus radio

["Aleksandr V. Piskunov" <aleksandr.v.piskunov@gmail.com>]

On Wed, Feb 03, 2010 at 07:33:20PM -0500, Andy Walls wrote:
> On Tue, 2010-02-02 at 13:29 -0200, Mauro Carvalho Chehab wrote:
> > Hi Andy,
> > 
> > This patch has never been applied or nacked. From your last comment, it
> > seems that you're waiting for Aleksandr Signed-of-by:.
> > 
> > If this is still the case, I suggest you to wait for a couple days. If he doesn't
> > send it, it is safe to add it without his SOB, since it is really a trivial change.
> 
> I'd like to look at this one once more.  The extra 50 ms and another
> reset may be avoidable.
> 
> cx25840-core.c:set_input() gets called for s_frequency so I'd like not
> to add 50 ms if not needed.

This patch is ugly, thats why no SOB was provided by me :)
Delaying every frequency change by 50 ms is no-go.

One possible solution is to mess with audio controller registers only when its really
required: when standard has to be changed, when TV<->Radio switch occurs, etc.

I have a patch that does something like this, will mail when get to PC with that card
and retest it.

As far as I remember there was another codepath that 100% triggers tinny audio, perhaps
it was a change of sampling rate.

> 
> Regards,
> Andy
> 
> > Cheers,
> > Mauro.
> > 
> > Andy Walls wrote:
> > > On Sun, 2009-10-11 at 04:01 +0300, Aleksandr V. Piskunov wrote:
> > >> On Tue, Oct 06, 2009 at 11:11:59AM +0300, Aleksandr V. Piskunov wrote:
> > >>> On Tue, Oct 06, 2009 at 11:04:06AM +0300, Aleksandr V. Piskunov wrote:
> > >>>> Added FM radio support to Avermedia AVerTV MCE 116 Plus card
> > >>>>
> > >>> What leaves me puzzled, radio only works ok with ivtv newi2c=1
> > >>>
> > >>> With default newi2c audio is tinny, metallic, with some strange static.
> > >>> Similar problem with pvr-150 was reported years ago, guess issue is still
> > >>> unresolved, perhaps something with cx25840..
> > >> This particular "tinny" audio problem is definitely I2C speed related, to be
> > >> more precise, audio only goes bad if i2c-algo-bit is being run with udelay
> > >> less than 15, i.e. i2c bus frequency is higher than 30 KHz.
> > >>
> > >> So with default udelay=10 or udelay=5 (optimal for IR reciever on that board)
> > >> radio goes bad. Running with newi2c=1 is ok, but again it isn't optimal for IR
> > >> reciever on AVerTV M116.
> > >>
> > >> I2C reads/writes to cx25840 themself are ok, verified using register readback
> > >> after each write/write4. Problem seems to be that with cx25840 register writes
> > >> coming too fast on higher i2c bus speed, switching register 0x808 _from_ 
> > >> TV standard autodetection mode (0xff) _to_ FM radio mode (0xf9) leaves chip 
> > >> audio detection routine in inconsistent state.
> > >>
> > >> The only solution I found is to do standard routine (assert_reset + write +
> > >> deassert_reset) followed by 50ms delay and another reset.
> > >>
> > >> Following patch works_for_me, can be improved to only delay/doublereset when
> > >> really needed, etc. Andy, could you comment/review?
> > > 
> > > Aleksandr,
> > > 
> > > Could you provide your Signed-off-by for this patch?  I'm going to
> > > commit it as is.
> > > 
> > > Thanks,
> > > Andy
> > > 
> > >> diff --git a/linux/drivers/media/video/cx25840/cx25840-core.c b/linux/drivers/media/video/cx25840/cx25840-core.c
> > >> --- a/linux/drivers/media/video/cx25840/cx25840-core.c
> > >> +++ b/linux/drivers/media/video/cx25840/cx25840-core.c
> > >> @@ -626,7 +642,13 @@
> > >>  	if (state->radio) {
> > >>  		cx25840_write(client, 0x808, 0xf9);
> > >>  		cx25840_write(client, 0x80b, 0x00);
> > >> -	}
> > >> +		/* Double reset cx2384x after setting FM radio mode, helps to
> > >> +		   avoid "tinny" audio when ivtv I2C bus is being run on
> > >> +		   frequency higher than 30 KHz */
> > >> +		cx25840_and_or(client, 0x810, ~0x01, 0);
> > >> +		msleep(50);
> > >> +		cx25840_and_or(client, 0x810, ~0x01, 1);
> > >> +	}	
> > >>  	else if (std & V4L2_STD_525_60) {
> > >>  		/* Certain Hauppauge PVR150 models have a hardware bug
> > >>  		   that causes audio to drop out. For these models the
> > >>
> > >> --
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> > 
>