[XS] Change in coreboot[main]: drivers/intel/gma: Add missing parentheses to brightness ACPI

[Jonathon Hall (Code Review)]

Attention is currently required from: Eric Lai, Felix Held, Felix Singer.

Hello Eric Lai, Felix Held, Felix Singer,

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/80260?usp=email

to look at the new patch set (#2).

Change subject: drivers/intel/gma: Add missing parentheses to brightness ACPI
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drivers/intel/gma: Add missing parentheses to brightness ACPI

Commit d25277666829 ("tree: Replace And(a,b) with ASL 2.0 syntax")
replaced two instances of `And(var, mask) == 0` with `var & mask == 0`.
This expression needs parentheses - `(var & mask) == 0`.

Without parentheses, it is always false, since the masks are nonzero
(`var & (mask == 0)`; `var & 0`; `0`).

This caused brightness changes on Intel GMA to take longer than
normal since the status was never checked.  The brightness would
change immediately, but another brightness change could not occur until
the first change timed out.

This was most noticeable in KDE, which waits for the brightness change
to complete before accepting another brightness up/down keypress.
Tapping brightness up/down repeatedly would take much longer to reach
max/min brightness due to many presses being ignored.

It is noticeable in GNOME as well but less obvious.  Tapping brightness
up/down repeatedly would handle all keypresses, but the display's
actual brightness would lag behind and skip some intermediate steps.

I tested both Librem 13v2 and Librem 14, as far as I know this would
apply to all systems configuring brightness with Intel GMA.

Test: Verify brightness keys respond quickly again on Librem 13v2 / 14.

Change-Id: I57895e8c654c83368b452d7adfe1856c0a0341fb
Signed-off-by: Jonathon Hall 
---
M src/drivers/intel/gma/acpi/configure_brightness_levels.asl
1 file changed, 2 insertions(+), 2 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/60/80260/2