Re: Interrupts disabled for too long in printk

From: Miquel van Smoorenburg
Date: Thu Jun 08 2006 - 14:33:26 EST


In article <9e4733910606080845y48dabed1o333b82eeb1a57381@xxxxxxxxxxxxxx>,
Jon Smirl <jonsmirl@xxxxxxxxx> wrote:
>This just seems to be an issue with the serial console implementation
>which is much slower. So the answer looks to be that if the serial
>console buffer is full, and it is being called with interrupts off, it
>should just toss the printk.

Read the serial console code. It is a standalone implementation
completely seperate from the standard drivers, which deliberately
turns off the interrupts and reverts to polling. This because
there is no guarantee the whole irq handling stuff still works
at the moment you're printk'ing a panic.

Also the current standard serial drivers only work if the
tty has been opened by a userspace process.

If you want to change this, first fix the latter problem, then
change the serial console output driver so that it uses the
standard serial driver for lower priority messages and only
uses the polling code for panics.

Mike.

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