On Wed, Jul 05, 2006 at 05:59:29PM -0600, Robert Hancock wrote: > Henrique de Moraes Holschuh wrote: > >HDAPS talks to the embedded controller using IO over the LPC bus, and not > >to > >the accelerometer chip or to a simple A/D i2c chip which is used excusively > >for accelerometer access. The EC interface for HDAPS data retrieval is > >not friendly to any errors, and hardlocks the machine somehow if any > >firmware bugs hit or if we violate any of the rules (that are not written > >anywhere) about how to access the EC without geting the SMBIOS unhappy. > > > >So, turning off HDAPS polling while it is not necessary really looks like a > >good idea overall. > > > >We are investigating the ACPI global lock as a way to at least get the > >SMBIOS to stay away from the EC while we talk to it, but we don't know if > >the entire SMBIOS firmware respects that lock. > > It had better, that is exactly what the ACPI Global Lock is supposed to > prevent (concurrent access to non-sharable resources between the OS and > SMI code). The ACPI DSDT contains information on whether or not the > machine requires the Global Lock in order to access the EC or whether it > is safe to access without locking. Isn't that vaild only if you actully use ACPI to access the EC? (AFAIK the HDAPS driver does direct port access.) -- Vojtech Pavlik Director SuSE Labs
