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SubjectRe: [linux-fbdev] Re: console spin_lock
On 18 Jan 01 at 0:49, Andrew Morton wrote:

> Assumption:
> - Once the system is up and running, it's always safe to
> call down() when in_interrupt() returns false - probably
> not the case in parts of the exit path - tough.
>
> Anyway, that's the thoughtware. Sound sane?

Do not forget to handle printk() done by fbdev driver... It
may invoke printk() from user context, but with console_semaphore
already held... Something like reentrant_semaphore? Also, we
should declare which console/fbdev function can printk/can schedule
and which must not, as using interrupts & schedule could yield
CPU to other tasks when (hardware assisted) operation is performed.
Some of them (clear, bmove) can take loong time to finish.
Best regards,
Petr Vandrovec
vandrove@vc.cvut.cz

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