On Mon, Nov 18, 2019 at 04:35:56PM +0100, Hans de Goede wrote:
> The Acer Switch 10 SW5-032 _LID method is quite broken, it looks like this:
>
> Method (_LID, 0, NotSerialized) // _LID: Lid Status
> {
> If ((STAS & One))
> {
> Local0 = One
> PBCG |= 0x05000000
> HMCG |= 0x05000000
> }
> Else
> {
> Local0 = Zero
> PBCG &= 0xF0FFFFFF
> HMCG &= 0xF0FFFFFF
> }
>
> ^^PCI0.GFX0.CLID = Local0
> Return (Local0)
> }
>
> The problem here is the accesses to the PBCG and HMCG, these are the
> pinconf0 registers for the power, resp. the home button GPIO,
> e.g. PBCG is declared as:
>
> OperationRegion (PWBT, SystemMemory, 0xFED0E080, 0x10)
> Field (PWBT, DWordAcc, NoLock, Preserve)
> {
> PBCG, 32,
> PBV1, 32,
> PBSA, 32,
> PBV2, 32
> }
>
> Where 0xFED0E000 is the base address of the GPO2 device and 0x80 is
> the offset for the pin used for the powerbutton.
>
> The problem here is this line in _LID:
> PBCG |= 0x05000000
>
> This changes the trigger flags of the GPIO, changing when it generates
> interrupts. Note it does not clear the original flags. Linux uses an
> edge triggered interrupt on both positive and negative edges. This |=
> adds the BYT_TRIG_LVL flag to this, so now it is turned into a level
> interrupt which fires both when low and high, iow it simply always
> fires leading to an interrupt storm, the tablet immediately waking up
> from suspend again, etc.
Hmm, does it work in Windows?
> There is nothing we can do to fix this, except for a DSDT override,
> which the user needs to do manually. The only thing we can do is
> never call _LID, which requires disabling the lid-switch functionality
> altogether.
>
> This commit adds a quirk for this, as no lid-switch function is better
> then the interrupt storm. A user manually applying a DSDT override can
> also override the quirk on the kernel cmdline.
>
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Reviewed-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
