Re: [PATCH] Readd panic blinking in 2.6

From: Andi Kleen
Date: Thu Sep 30 2004 - 03:45:40 EST


>
> Something like
>
> spin_lock_irqsave(&i8042_lock, flags);
> i8042_flush();
> i8042_ctr &= ~I8042_CTR_KBDINT & ~I8042_CTR_AUXINT;
> i8042_command(&i8042_ctr, I8042_CMD_CTL_WCTR);
> i8042_wait_write();
> i8042_write_data(0xed);
> i8042_wait_read();
> i8042_flush();
> i8042_wait_write();
> i8042_write_data(led);
> i8042_wait_read();
> i8042_flush();
> spin_unlock_irqrestore(&i8042_lock, flags);
>
> would be safer and more correct.

That all takes far too many locks. The risk of deadlocking during
panic is too great. I think the delay is fine (worked great under 2.4),
just need to fix the IBF issue you mentioned.

-Andi

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