On Fri, Jul 26, 2019 at 07:57:06PM +0200, Pavel Machek wrote:
On Wed 2019-07-24 21:19:14, Greg Kroah-Hartman wrote:
[ Upstream commit 44758bafa53602f2581a6857bb20b55d4d8ad5b2 ]
ACPI GPEs (other than the EC one) can be enabled in two situations. First, the GPEs with existing _Lxx and _Exx methods are enabled implicitly by ACPICA during system initialization. Second, the GPEs without these methods (like GPEs listed by _PRW objects for wakeup devices) need to be enabled directly by the code that is going to use them (e.g. ACPI power management or device drivers).
In the former case, if the status of a given GPE is set to start with, its handler method (either _Lxx or _Exx) needs to be invoked to take care of the events (possibly) signaled before the GPE was enabled. In the latter case, however, the first caller of acpi_enable_gpe() for a given GPE should not be expected to care about any events that might be signaled through it earlier. In that case, it is better to clear the status of the GPE before enabling it, to prevent stale events from triggering unwanted actions (like spurious system resume, for example).
Given the complexity of ACPI and number of implementations, I don't think this is safe for stable.
So it's better to have a regression later rather than sooner?
Notebooks are not part of automated test farms, so it did not get nearly enough testing...
But by finding problems with a patch when it is closer to having been created is always better than waiting 6+ months to find the issue then.
And if this patch does cause problems, we can easily revert it.
thanks,
greg k-h