[PATCH v2 1/3] PATA host controller driver for ep93xx

On 2012-04-03 22:08, Arnd Bergmann wrote:

quoted

quoted

+static void ep93xx_pata_wait_for_iordy(void __iomem *base)
+{
+     unsigned long deadline = jiffies + msecs_to_jiffies(1000);
+     while (!ep93xx_pata_check_iordy(base) &&
+             time_is_before_jiffies(deadline))
+             cpu_relax();
+}

Much better for a delay than the previous version. However, it's
still a busy wait, which is bad for realtime behavior, especially
since this can potentially take many milliseconds. If possible,
it should have an msleep() or at least cond_resched() instead of
the cpu_relax(). Obviously that will only work when no spinlocks
are held.

Unfortunately, we can't use msleep() or cond_resched() here
- ep93xx_pata_wait_for_iordy() is called from interrupt handler.

Thanks,
RP