Interrupt handling

[Darshan Ghumare]

---------- Forwarded message ----------
From: Darshan Ghumare <darshan.ghumare at gmail.com>
Date: Wed, Feb 16, 2011 at 10:14 AM
Subject: Re: Interrupt handling
To: Mulyadi Santosa <mulyadi.santosa at gmail.com>



Sir,

>
> On Tue, Feb 15, 2011 at 4:16 PM, Mulyadi Santosa <
> mulyadi.santosa at gmail.com> wrote:
>
>> Hi... :)
>>
>> On Tue, Feb 15, 2011 at 16:08, Darshan Ghumare
>> <darshan.ghumare at gmail.com> wrote:
>> > Sir,
>> > On x86 UP (Single CPU), Can lower priority (say) IRQ5 preempt higher one
>> > (say) IRQ4 (Currently, CPU is executing interrupt handler of IRQ4)?
>>
>> In Linux kernel, I never heard such irq prioritizing. Linux kernel
>> does general preemption such that any code path could preempt other
>> code path as long as preemption is allowed at that point and/or
>> interrupt is enabled (which one affect the situation depends on type
>> of code path).
>>
>
> IMHO, When the Processor is executing interrupt handler of IRQ4 then
> Processor is the one which pushes SS, SP, EFLAGS, CS  & EIP  on stack (in
> this case this will all corresponds to interrupt handler of IRQ4) & loads CS
> & EIP corresponding to IRQ5.
> So, how come its depends on OS (kernel)? Please correct me if I am wrong.
>
>
>> But, vaguely I read that Windows kernel does that.... that's why in
>> certain BSOD you read message prefixed with "IRQL xxx xxx xxxx". That
>> means lower interrupt handler somehow preempt higher one and that's
>> not allowed.
>>
>> It comes from my raw observation so things might be wrong somewhere...
>>
>> --
>> regards,
>>
>> Mulyadi Santosa
>> Freelance Linux trainer and consultant
>>
>> blog: the-hydra.blogspot.com
>> training: mulyaditraining.blogspot.com
>>
>



-- 
Darshan®
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20110216/9e8390ca/attachment.html