From: Jens Axboe <axboe@suse.de>
To: gundolfk@web.de
Cc: Christoph Bartelmus <lirc@bartelmus.de>, linux-kernel@vger.kernel.org
Subject: Re: IRQ blocking when reading audio CDs
Date: Mon, 27 Sep 2004 07:52:38 +0200 [thread overview]
Message-ID: <20040927055234.GA2288@suse.de> (raw)
In-Reply-To: <20040926120849.GG3134@lilienthal>
On Sun, Sep 26 2004, Gundolf Kiefer wrote:
> Dear Jens (& Christoph),
>
> on my media PC (a Pentium II 350 MHz running Debian Woody with Kernel
> 2.4.25), I have problems using LIRC 0.6.6 with a serial IR reveiver when at
> the same time some application (cdparanoia, xmms/Audio CD reader) is
> reading audio data from a CD.
>
> After some testing and exploration of the LIRC source code, I figured out
> that during audio CD reading interrupts seem to be blocked for a longer
> time (in the order of milliseconds), while lirc_serial measures the exact
> time between two serial interrupts and thus relies on an accurate timing.
> In consequence, LIRC does not recognize the IR sequences, there are no
> errors reported. Assigning a high priority to the serial interrupt using
> "irq_tune" did not help.
>
> Is there a way to make the audio CD read operations less blocking? Or does
> any of you know a different source of the problem I observed?
Upgrade to 2.6, it can use DMA for cdda extraction. If you cannot for
some reason, Andrew had an ide-cd hack to enable dma in 2.4 for this.
--
Jens Axboe
next prev parent reply other threads:[~2004-09-27 5:55 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-26 12:08 IRQ blocking when reading audio CDs Gundolf Kiefer
2004-09-27 5:52 ` Jens Axboe [this message]
2004-09-28 19:21 ` Lee Revell
2004-09-29 18:46 ` Gundolf Kiefer
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