[alsa-devel] MTP-AV Bugs

[Takashi Iwai]

At Wed, 11 Feb 2009 14:18:59 +0100,
Holger Dehnhardt wrote:
> 
> Dear Takashi,
> 
> thank you for your quick response!
> See my inline comments.
> 
> Am Mittwoch, 11. Februar 2009 13:08:22 schrieb Takashi Iwai:
> > At Tue, 10 Feb 2009 21:54:32 +0100,
> >
> > Holger Dehnhardt wrote:
> > > After some time I found the following bug:
> > >
> > > static void snd_mtpav_inmidi_h(struct mtpav *mcrd, u8 inbyte)
> > > {
> > >         if (inbyte >= 0xf8) {
> > >                 /* real-time midi code */
> > > -->                snd_mtpav_inmidi_process(mcrd, inbyte);
> > > 	//here the inmidiport is not translated to the prtnumber, so
> > > 	// snd_mtpav_inmidi_process the port with an index of some 80000
> > > 	// in the ports array of the mtpav struct was called
> >
> > Good catch.  I think the patch below should fix the problem

Did you try my patch?


> > > The following change made the driver work:
> > > static void snd_mtpav_inmidi_h(struct mtpav *mcrd, u8 inbyte)
> > > {
> > >         if (inbyte >= 0xf8) {
> > >                 /* real-time midi code */
> > > 		mcrd->inmidiport = translate_hwport_to_subdevice(mcrd, inbyte);
> >
> > This isn't correct since inbyte is supposed to be under 0x13.
> 
> Sorry, I don't understand what you mean: inbyte should always be lower than 
> 0x13 or is the real time midi code always lower then 0x13? 

I meant that the data passed to translate_hwport_to_subdevice() is
supposed to be <= 0x13.  In that code path, inbyte is >= 0xf8, thus
you pass an invalid data.


> > > After that I realised, that with the recent driver - even without my
> > > change - playing midi files din not work anymore.
> > > Only the first midi event was sent to the interface, everything else was
> > > dropped somewhere.
> > >
> > > So a diff between the last workin version and the recent version showed
> > > only one change:
> >
> > What was the last working version exactly?
> 
> 1.0.18 (from the debian experimental repository)

Weird.  There is really no essential change since that.
Are you sure that you just copied 1.0.18 mtpav.c fixes the problem?


thanks,

Takashi