Messages in this thread | | | Date | Tue, 5 Nov 2002 20:08:54 +0100 | From | Willy Tarreau <> | Subject | Re: [PATCH] Re: time() glitch on 2.4.18: solved |
| |
On Tue, Nov 05, 2002 at 01:57:16PM -0500, Richard B. Johnson wrote:
> No! You will break many machines. You cannot use out_p() when > writing the latch it __must__ be out(). the "_p" puts a write > to another port between the two writes. That will screw up > the internal state-machine of most PITs including AMD-SC520.
You make an interesting point. Have you checked if an inb_p() on this hardware could unlock the latch when reading the first byte ? It may also be one cause of time jumps if the counter is just about to wrap when it's being read, and gets unlocked by an out to port 0x80 (the "_p").
> count = inb_p(0x40); /* read the latched count */ > count |= inb(0x40) << 8;
Or perhaps it will be time to change port 0x80 to something else, that no chipset will use. I've seen 0xED in a bios somewhere, but I don't remember where.
Cheers, Willy
- 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/
| |