Messages in this thread | | | Date | Wed, 04 Apr 2001 11:54:35 -0700 | From | Miles Lane <> | Subject | Re: Contacts within AMD? AMD-756 USB host-controller blacklisted due to |
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Thomas Dodd wrote:
> Alan Cox wrote: > >>> 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? >> >> We are working on that currently via the Red Hat contact. >> >> >>> 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. >> >> because we dont know the full scope of the problem yet. > > > Exactly how many bug reports has this caused? > What kind of problems? > > I know I had trouble onece, but it was a CONFIG problem > with the 2.4.2ac series and the extra DEBUG options.
I think probably everyone who has an AMD-756 has reported this error. At least, I've not seen any messages from people saying, "I have an AMD-756 and have never seen this error." Most of the time, when the error occurs, it seems pretty benign. That is, I haven't noticed it crashing USB device connections, causing data corruption or OOPSen. Some folks _have_ reported OOPSen, though, that seemed to be triggered by the erratum #4 hardware bug. I think I may have had one of these a long time ago.
I believe David has found that there definitely are code paths where this hardware bug can cause failures of various sorts and that's why the AMD-756 has been blacklisted. I don't believe these failure code paths have anything to do with specific debugging configurations.
David/Alan, please correct me if I've got this all wrong.
Thanks, Miles
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