2000-11-12 13:56:54

by Alexander V. Lukyanov

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Subject: sound problems caused by masking irq for too long

Hi!

In some cases sound gets interrupted for a moment, this happens in two
occasions. When unmaskirq flag is off on ide cdrom and it is accessed,
and when tdfxfb console (800x600) flashes (tput flash, or `set bell-style
visible' in .inputrc).

It seems the problem is caused by masking irq for too long, and then
the sound dma buffer underruns. This is fixed by unmasking irq for ide
cdrom by `hdparm -u1 /dev/cdrom', and by changing spin_(un)lock_irq
in console.c to spin_(un)lock_bh.

This was observed on 2.4.0-pre10, the problem with ide also exists on
2.2.17, the console.c in 2.2.17 only disables CONSOLE_BH.

The audio card is old awe32 (isa), sound driver is modular.

--
Alexander.


2000-11-12 15:09:33

by Igmar Palsenberg

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Subject: Re: sound problems caused by masking irq for too long

On Sun, 12 Nov 2000, Alexander V. Lukyanov wrote:

> Hi!
>
> In some cases sound gets interrupted for a moment, this happens in two
> occasions. When unmaskirq flag is off on ide cdrom and it is accessed,
> and when tdfxfb console (800x600) flashes (tput flash, or `set bell-style
> visible' in .inputrc).
>
> It seems the problem is caused by masking irq for too long, and then
> the sound dma buffer underruns. This is fixed by unmasking irq for ide
> cdrom by `hdparm -u1 /dev/cdrom', and by changing spin_(un)lock_irq
> in console.c to spin_(un)lock_bh.
>
> This was observed on 2.4.0-pre10, the problem with ide also exists on
> 2.2.17, the console.c in 2.2.17 only disables CONSOLE_BH.

The above story also explains why my sound 'hickups' when I switch from
console to X (yes, and I do that a lot).

Is this a recent change from 2.2.15 -> >= 2.2.16 or so ?

> The audio card is old awe32 (isa), sound driver is modular.

This is a SB16 PnP



Igmar