Messages in this thread Patch in this message | | | From | Russell King <> | Subject | Re: patch: delay_50ms() in ide-probe.c in 2.2.14 | Date | Sun, 20 Feb 2000 14:32:43 +0000 (GMT) |
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arijort@valinux.com writes: > Simple arithmetic tells me this patch > > a) produces same behavior as previous code, and > b) does it with fewer calculations. > > So it has to be good, right? > But then how do we exit the while loop? > How does jiffies change? > > This patch applies cleanly against 2.2.14 > Against 2.3.45, the relevant file is ide.c > but otherwise, it's clean.
It's also wrong. (HZ + 39)/20 is constant, and you therefore have effectively a while(1); loop there now.
(Hint: 'jiffies' is updated in an interrupt routine which is enabled throughout this function).
> --- drivers/block/ide-probe.c.orig Sun Feb 20 00:46:54 2000 > +++ drivers/block/ide-probe.c Sun Feb 20 07:28:32 2000 > @@ -154,8 +154,7 @@ > */ > static void delay_50ms (void) > { > - unsigned long timeout = jiffies + ((HZ + 19)/20) + 1; > - while (0 < (signed long)(timeout - jiffies)); > + while (0 < (signed long)((HZ + 39)/20)); > } > > /* _____ |_____| ------------------------------------------------- ---+---+- | | Russell King rmk@arm.linux.org.uk --- --- | | | | http://www.arm.linux.org.uk/~rmk/aboutme.html / / | | +-+-+ --- -+- / | THE developer of ARM Linux |+| /|\ / | | | --- | +-+-+ ------------------------------------------------- /\\\ | - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
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