On Mon, Apr 08, 2002 at 04:33:49PM +1000, Neale Banks wrote:
> Hi Vojtech,
>
> Appended patch:
>
> (a) merges your patch of November 2001 into 2.2.21rc3
> (b) adds a boot-time option to explicitly disable the via-timer hacks.
>
> I've been using this patch for a while, but haven't subjected it to more
> thorough testing than that it boots OK and doesn't appear to complicate
> anything (I might be able to trigger the relevant condition by running the
> battery right down on my (old) AcerNote-950, but one of the last times
> this happened I also got some pretty nasty file system corruption - so I'm
> not too keen to try that one again :-| ).
>
> Anyway, does this patch and my merge of it look correct?
Looks OK.
>
> Thanks,
> Neale.
>
> --- linux-2.2.21-rc3-orig/arch/i386/kernel/time.c Mon Mar 26 02:37:30 2001
> +++ linux-2.2.21-rc3-ntb/arch/i386/kernel/time.c Fri Apr 5 23:04:13 2002
> @@ -81,6 +81,8 @@
>
> spinlock_t rtc_lock = SPIN_LOCK_UNLOCKED;
>
> +static int via686a_hacks = 1; /* default to enabled */
> +
> static inline unsigned long do_fast_gettimeoffset(void)
> {
> register unsigned long eax asm("ax");
> @@ -111,6 +113,54 @@
> return delay_at_last_interrupt + edx;
> }
>
> +/*
> + * VIA hardware bug workaround with check if it is really needed and
> + * a printk that could tell us what's exactly happening on machines which
> + * trigger the check, but are not VIA-based.
> + *
> + * Must be called with the i8253_spinlock held.
> + */
> +
> +static void via_reset_and_whine(int *count)
> +{
> + static unsigned long last_whine = 0;
> + unsigned long new_whine;
> + int count2;
> +
> + new_whine = last_whine;
> +
> + outb_p(0x00, 0x43); /* Re-read the timer */
> + count2 = inb_p(0x40);
> + count2 |= inb(0x40) << 8;
> +
> + if (time_after(jiffies, last_whine)) {
> + printk(KERN_WARNING "timer.c: VIA bug check triggered. "
> + "Value read %d [%#x], re-read %d [%#x]\n",
> + *count, *count, count2, count2);
> + new_whine = jiffies + HZ;
> + }
> +
> + *count = count2;
> +
> + if (count2 > LATCH) { /* Still bad */
> + if (time_after(jiffies, last_whine)) {
> + printk(KERN_WARNING "timer.c VIA bug really present. ");
> + new_whine = jiffies + HZ;
> + }
> + if (via686a_hacks) {
> + printk(KERN_WARNING "Resetting PIT timer.\n");
> + outb_p(0x34, 0x43);
> + outb_p(LATCH & 0xff, 0x40);
> + outb(LATCH >> 8, 0x40);
> + } else {
> + printk(KERN_WARNING "But VIA hacks disabled.\n");
> + }
> + *count = LATCH - 1;
> + }
> +
> + last_whine = new_whine;
> +}
> +
> #define TICK_SIZE tick
>
> #ifndef CONFIG_X86_TSC
> @@ -177,12 +227,8 @@
> count |= inb_p(0x40) << 8;
>
> /* VIA686a test code... reset the latch if count > max */
> - if (count > LATCH-1) {
> - outb_p(0x34, 0x43);
> - outb_p(LATCH & 0xff, 0x40);
> - outb(LATCH >> 8, 0x40);
> - count = LATCH - 1;
> - }
> + if (count > LATCH)
> + via_reset_and_whine(&count);
>
> /*
> * avoiding timer inconsistencies (they are rare, but they happen)...
> @@ -478,19 +524,8 @@
> count |= inb(0x40) << 8;
>
> /* VIA686a test code... reset the latch if count > max */
> - if (count > LATCH-1) {
> - static int last_whine;
> - outb_p(0x34, 0x43);
> - outb_p(LATCH & 0xff, 0x40);
> - outb(LATCH >> 8, 0x40);
> - count = LATCH - 1;
> - if(time_after(jiffies, last_whine))
> - {
> - printk(KERN_WARNING "probable hardware bug: clock timer configuration lost - probably a VIA686a.\n");
> - printk(KERN_WARNING "probable hardware bug: restoring chip configuration.\n");
> - last_whine = jiffies + HZ;
> - }
> - }
> + if (count > LATCH)
> + via_reset_and_whine(&count);
>
> #if 0
> spin_unlock(&i8253_lock);
> @@ -737,3 +772,25 @@
> setup_x86_irq(0, &irq0);
> #endif
> }
> +
> +static int __init timer_setup(char *str)
> +{
> + int invert;
> +
> + while ((str != NULL) && (*str != '\0')) {
> + invert = (strncmp(str, "no-", 3) == 0);
> + if (invert)
> + str += 3;
> + if (strncmp(str, "via686a", 7) == 0) {
> + via686a_hacks = !invert;
> + if (invert)
> + printk(KERN_INFO "timer: VIA686a workaround disabled.\n");
> + }
> + str = strchr(str, ',');
> + if (str != NULL)
> + str += strspn(str, ", \t");
> + }
> + return 1;
> +}
> +
> +__setup("timer=", timer_setup);
-- Vojtech Pavlik SuSE Labs - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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