Messages in this thread | | | Date | Tue, 03 Apr 2001 10:46:43 -0700 | From | Miles Lane <> | Subject | Contacts within AMD? AMD-756 USB host-controller blacklisted due to erratum #4. |
| |
Running 2.4.2-ac28, I get the following error:
usb-ohci.c: 00:07.4 (Advanced Micro Devices [AMD] AMD-756 [Viper] USB): blacklisted, erratum #4
David Brownell recently added this check to the usb-ohci driver since noone has gotten information from AMD for the workaround, which is rumored to exist, for this bug.
Do any of you have contacts within AMD who might be able to get an explanation of the workaround to David Brownell?
The bug is that the NDP value sent by the AMD-756 is sometimes bogus. The following examples, collected before the chip was blacklisted, show the failure. As you can see, the bogus value given varies. Rereading NDP seems to give a valid value. I am not really clear why we don't simply read the value twice whenever the host-controller is detected to be an AMD-756.
Mar 4 17:20:52 aerie kernel: usb-ohci.c: bogus NDP=128 for OHCI usb-00:07.4 Mar 4 17:20:52 aerie kernel: usb-ohci.c: rereads as NDP=4
Mar 4 17:50:29 aerie kernel: usb-ohci.c: bogus NDP=245 for OHCI usb-00:07.4 Mar 4 17:50:29 aerie kernel: usb-ohci.c: rereads as NDP=4
Mar 6 21:11:07 aerie kernel: usb-ohci.c: bogus NDP=210 for OHCI usb-00:07.4 Mar 6 21:11:07 aerie kernel: usb-ohci.c: rereads as NDP=4
Thanks, Miles - 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/
| |