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From: Moore, R. <rob...@in...> - 2007-02-07 20:35:42
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Handles from a DSDT are in fact permanent. Once a SSDT is unloaded, however, those handles are invalid. We are considering making these handles "real" handles instead of simply pointers to catch the use of an invalid handle. > -----Original Message----- > From: lin...@vg... [mailto:linux-acpi- > ow...@vg...] On Behalf Of Henrique de Moraes Holschuh > Sent: Wednesday, February 07, 2007 11:44 AM > To: lin...@vg... > Cc: ibm...@li... > Subject: Caching the results of acpi_get_handle() in a driver: is it > valid? >=20 > The code I inherited in ibm-acpi does heavy caching of acpi_get_handle() > results. It stores the results of acpi_get_handle() for a number of nodes > at module init, and uses the stored results during its lifetime. >=20 > Is that a valid use of the handles returned by acpi_get_handle()? In > particular, what happens to handlers when a SSDT gets loaded or unloaded > at > runtime? Do handles that came from the DSDT change? What if the handler > was to a node in the SSDT being unloaded? What if the handler is > overriden > by a new loaded SSDT? >=20 > While the vast majority of the handlers ibm-acpi caches are in the DSDT > and > very unlikely to change through a SSDT load, I'd still like to make sure > the > driver is doing the right thing... >=20 > PS: not caching the results is always possible, but that will mean various > calls to acpi_get_handle() per second. >=20 > -- > "One disk to rule them all, One disk to find them. One disk to bring > them all and in the darkness grind them. In the Land of Redmond > where the shadows lie." -- The Silicon Valley Tarot > Henrique Holschuh > - > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to maj...@vg... > More majordomo info at http://vger.kernel.org/majordomo-info.html |
