Re: aplsmc(4): disable backlight when lid is closed

[Tobias Heider]

On Thu, Nov 24, 2022 at 08:36:48PM +0100, Mark Kettenis wrote:
> > Date: Thu, 24 Nov 2022 19:04:03 +0100
> > From: Tobias Heider <tobias.hei...@stusta.de>
> > 
> > The diff below disables the screen backlight on apple silicon macs when the
> > lid is closed.
> 
> Can we distinguish lid close events from lid open events?  Might make
> more sense to base the decision to turn the display off based on that
> instead of toggling a variable.
> 
> > Normally, we suspend or hibernate depending on the value of
> > machdep.lid_action.  Since suspend doesn't work reliably yet I think
> > this is a good intermediate solution to save some power while the
> > laptop is idling.
> 
> Even though acpibtn(4) documents 0 as "Do nothing", doesn't it make
> sense to always turn off the display backlight when the lid gets
> closed?
> 
> Then we could actually implement 1 as suspend but just set lid_action
> to 0?

Ok, so let's leave lid_action out of this for now and unconditionally
blank/unblank on lid events. How do you like this?

Index: arch/arm64/dev/aplsmc.c
===================================================================
RCS file: /cvs/src/sys/arch/arm64/dev/aplsmc.c,v
retrieving revision 1.18
diff -u -p -r1.18 aplsmc.c
--- arch/arm64/dev/aplsmc.c     14 Nov 2022 11:11:17 -0000      1.18
+++ arch/arm64/dev/aplsmc.c     24 Nov 2022 22:24:13 -0000
@@ -37,6 +37,8 @@
 
 #include "apm.h"
 
+extern void (*simplefb_burn_hook)(u_int);
+
 extern void (*cpuresetfn)(void);
 extern void (*powerdownfn)(void);
 
@@ -96,6 +98,10 @@ struct aplsmc_sensor {
 #define SMC_PWRBTN_TOUCHID     0x06
 #define SMC_PWRBTN_LONG                0xfe
 
+/* Lid events */
+#define SMC_LID_OPEN           0x00
+#define SMC_LID_CLOSE          0x01
+
 #define APLSMC_BE              (1 << 0)
 #define APLSMC_HIDDEN          (1 << 1)
 
@@ -372,7 +378,20 @@ aplsmc_handle_notification(struct aplsmc
                }
                break;
        case SMC_EV_TYPE_LID:
-               /* XXX Handle lid events. */
+               switch (SMC_EV_SUBTYPE(data)) {
+               case SMC_LID_OPEN:
+                       if (simplefb_burn_hook)
+                               simplefb_burn_hook(1);
+                       break;
+               case SMC_LID_CLOSE:
+                       if (simplefb_burn_hook)
+                               simplefb_burn_hook(0);
+                       break;
+               default:
+                       printf("%s: SMV_EV_TYPE_LID 0x%016llx\n",
+                              sc->sc_dev.dv_xname, data);
+                       break;
+               }
                break;
        default:
 #ifdef APLSMC_DEBUG