On 06/15/2011 08:17 PM, Matthew Garrett wrote: > On Wed, Jun 15, 2011 at 11:53:32AM +0800, Huang Ying wrote: >> Hi, Matthew, >> On 06/14/2011 10:52 PM, Matthew Garrett wrote: >>> And then tear down GHES. This seems wrong. A platform could predicate >>> APEI functionality on the ACPI spec APEI indication (which we currently >>> don't pass) without implementing WHEA, but with this patch we'd refuse >>> to enable GHES support? We should probably try both the standard method >>> and the WHEA method and only disable GHES if both fail. >> >> You means the "APEI Support" bit for standard UUID? Do you know which >> machine uses this bit? I can write the code, but I have no machine to >> test it. > > I have access to a Dell system that uses this. Great! Can you help us to test the code? >> BTW, it is better for us to enable APEI firmware first mode (that is, >> what is enabled by evaluating the WHEA UUID) after GHES reporting is >> ready (that is, after GHES module is successfully loaded). That is >> later than current ACPI _OSC evaluation with standard UUID. Is it >> possible to evaluate _OSC with standard UUID twice? So that we can >> enable APEI firmware first mode later. > > Urgh. One machine I've looked at enables APEI if the WHEA _OSC call is > made, and then clears a flag if any other _OSC call is made. In that > specific case it doesn't seem to matter (the flag never actually gets > checked in any of the other codepaths), but it seems that the intention > is for the generic call to be made and the WHEA one to be made after > that. Yes. The WHEA call should be made after the generic one. Another situation is as follow: - Generic _OSC call without "APEI Support" bit is called (in acpi_bus_osc_support). - After some time, when we think it is good to turn on firmware first mode fully, usually after we checking HEST and initializing corresponding module, we make generic _OSC call with "APEI Support" bit to turn on firmware first mode fully in standard way. Is it a good idea to make generic _OSC call twice, one without "APEI Support" bit, the other with "APEI Support" bit? Best Regards, Huang Ying -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
