---------- Forwarded message ---------- From: Darshan Ghumare <[email protected]> Date: Wed, Feb 16, 2011 at 10:14 AM Subject: Re: Interrupt handling To: Mulyadi Santosa <[email protected]>
Sir, > > On Tue, Feb 15, 2011 at 4:16 PM, Mulyadi Santosa < > [email protected]> wrote: > >> Hi... :) >> >> On Tue, Feb 15, 2011 at 16:08, Darshan Ghumare >> <[email protected]> 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®
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