[src/trunk]: src/sys/dev/acpi acpiout(4): Work around firmware that doesn't l...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/cff30dd9b4b7
branches:  trunk
changeset: 1029297:cff30dd9b4b7
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Thu Dec 30 14:40:06 2021 +0000

description:
acpiout(4): Work around firmware that doesn't like some brightnesses.

Instead of just asking for cur - 5 or cur + 5, repeatedly ask for
that increment, check whether we actually made progress in that
direction, and if not keep going with another increment, until we hit
the bounds of brightness levels.

I can't find anything in the ACPI spec about this, but my laptop
seems to have trouble with certain levels: 15, 75, 85, 95.  It goes
in all other increments of 5 from 5 to 100, just not those ones --
acts as if the change just never happened, so with the old logic the
brightness up/down would get stuck unable to move in either
direction.

This should have no impact on machines where the first increment
actually takes.

diffstat:

 sys/dev/acpi/acpi_display.c |  60 +++++++++++++++++++++++++++------------------
 1 files changed, 36 insertions(+), 24 deletions(-)

diffs (102 lines):

diff -r 38e21d480ca3 -r cff30dd9b4b7 sys/dev/acpi/acpi_display.c
--- a/sys/dev/acpi/acpi_display.c       Thu Dec 30 04:57:10 2021 +0000
+++ b/sys/dev/acpi/acpi_display.c       Thu Dec 30 14:40:06 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: acpi_display.c,v 1.20 2021/08/07 16:19:09 thorpej Exp $        */
+/*     $NetBSD: acpi_display.c,v 1.21 2021/12/30 14:40:06 riastradh Exp $      */
 
 /*-
  * Copyright (c) 2010 The NetBSD Foundation, Inc.
@@ -66,7 +66,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: acpi_display.c,v 1.20 2021/08/07 16:19:09 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: acpi_display.c,v 1.21 2021/12/30 14:40:06 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/device.h>
@@ -1010,7 +1010,8 @@
 {
        struct acpidisp_out_softc *osc = arg;
        struct acpidisp_brctl *bc = osc->sc_brctl;
-       uint8_t lo, up;
+       uint8_t max, lo, up;
+       int cur;
 
        if (bc == NULL) {
                /* Fallback to pmf(9). */
@@ -1019,16 +1020,21 @@
        }
 
        mutex_enter(osc->sc_mtx);
-
-       (void)acpidisp_get_brightness(osc, &bc->bc_current);
-
-       acpidisp_array_search(bc->bc_level, bc->bc_level_count,
-           bc->bc_current + ACPI_DISP_BRCTL_STEP, &lo, &up);
-
-       bc->bc_current = up;
-       (void)acpidisp_set_brightness(osc, bc->bc_current);
-
-       mutex_exit(osc->sc_mtx);
+       max = bc->bc_level[bc->bc_level_count - 1];
+       if (acpidisp_get_brightness(osc, &bc->bc_current))
+               goto out;
+       for (cur = bc->bc_current; (cur += ACPI_DISP_BRCTL_STEP) <= max;) {
+               acpidisp_array_search(bc->bc_level, bc->bc_level_count, cur,
+                   &lo, &up);
+               bc->bc_current = up;
+               if (acpidisp_set_brightness(osc, bc->bc_current))
+                       goto out;
+               if (acpidisp_get_brightness(osc, &bc->bc_current))
+                       goto out;
+               if (bc->bc_current >= cur)
+                       break;
+       }
+out:   mutex_exit(osc->sc_mtx);
 }
 
 static void
@@ -1036,7 +1042,8 @@
 {
        struct acpidisp_out_softc *osc = arg;
        struct acpidisp_brctl *bc = osc->sc_brctl;
-       uint8_t lo, up;
+       uint8_t min, lo, up;
+       int cur;
 
        if (bc == NULL) {
                /* Fallback to pmf(9). */
@@ -1045,16 +1052,21 @@
        }
 
        mutex_enter(osc->sc_mtx);
-
-       (void)acpidisp_get_brightness(osc, &bc->bc_current);
-
-       acpidisp_array_search(bc->bc_level, bc->bc_level_count,
-           bc->bc_current - ACPI_DISP_BRCTL_STEP, &lo, &up);
-
-       bc->bc_current = lo;
-       (void)acpidisp_set_brightness(osc, bc->bc_current);
-
-       mutex_exit(osc->sc_mtx);
+       min = bc->bc_level[0];
+       if (acpidisp_get_brightness(osc, &bc->bc_current))
+               goto out;
+       for (cur = bc->bc_current; (cur -= ACPI_DISP_BRCTL_STEP) >= min;) {
+               acpidisp_array_search(bc->bc_level, bc->bc_level_count, cur,
+                   &lo, &up);
+               bc->bc_current = lo;
+               if (acpidisp_set_brightness(osc, bc->bc_current))
+                       goto out;
+               if (acpidisp_get_brightness(osc, &bc->bc_current))
+                       goto out;
+               if (bc->bc_current <= cur)
+                       break;
+       }
+out:   mutex_exit(osc->sc_mtx);
 }
 
 static void