[alsa-devel] tea575x-tuner improvements & use in maxiradio

Hans Verkuil hverkuil at xs4all.nl
Wed Feb 8 08:29:25 CET 2012

On Tuesday, February 07, 2012 23:20:19 Ondrej Zary wrote:
> On Sunday 05 February 2012 14:17:05 Hans Verkuil wrote:
> > These patches improve the tea575x-tuner module to make it up to date with
> > the latest V4L2 frameworks.
> >
> > The maxiradio driver has also been converted to use the tea575x-tuner and
> > I've used that card to test it.
> >
> > Unfortunately, this card can't read the data pin, so the new hardware seek
> > functionality has been tested only partially (yes, it seeks, but when it
> > finds a channel I can't read back the frequency).
> >
> > Ondrej, are you able to test these patches for the sound cards that use
> > this tea575x tuner?
> >
> > Note that these two patches rely on other work that I did and that hasn't
> > been merged yet. So it is best to pull from my git tree:
> >
> > http://git.linuxtv.org/hverkuil/media_tree.git/shortlog/refs/heads/radio-pc
> >i2
> >
> > You can use the v4l-utils repository (http://git.linuxtv.org/v4l-utils.git)
> > to test the drivers: the v4l2-compliance test should succeed and with
> > v4l2-ctl you can test the hardware seek:
> >
> > To seek down:
> >
> > v4l2-ctl -d /dev/radio0 --freq-seek=dir=0
> >
> > To seek up:
> >
> > v4l2-ctl -d /dev/radio0 --freq-seek=dir=1
> >
> > To do the compliance test:
> >
> > v4l2-compliance -r /dev/radio0
> It seems to work (tested with SF64-PCR - snd_fm801) but the seek is severely 
> broken. Reading the frequency immediately after seek does not work, it always 
> returns the old value (haven't found a delay that works). Reading it later 
> (copied back snd_tea575x_get_freq function) works. The chip seeks randomly up 
> or down, ignoring UP/DOWN flag and often stops at wrong place (only noise) or 
> even outside the FM range.
> So I strongly suggest not to enable this (mis-)feature. The HW seems to be 
> completely broken (unless there's some weird bug in the code).

Well, it seemed like a good idea at the time :-) I'll remove this 'feature',
it's really not worth our time to try and make this work for these old cards.

I wonder if you are able to test the ISA radio-sf16fmr2.c driver? I'm not
sure if you have the hardware, but since I changed this driver to use the
proper isa kernel framework I'd like to have this tested if possible.



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