On Mon, 4 Jun 2018, Geert Uytterhoeven wrote:

quoted

Don't call pmu_shutdown() or pmu_restart() on early PowerBooks: the 
PMU device found in these PowerBooks isn't supported.

Shouldn't that be a separate patch?

quoted

--- a/arch/m68k/mac/misc.c
+++ b/arch/m68k/mac/misc.c

quoted

@@ -477,9 +445,8 @@ void mac_poweroff(void)
                   macintosh_config->adb_type == MAC_ADB_CUDA) {
                cuda_shutdown();
 #endif
-#ifdef CONFIG_ADB_PMU68K
-       } else if (macintosh_config->adb_type == MAC_ADB_PB1
-               || macintosh_config->adb_type == MAC_ADB_PB2) {
+#ifdef CONFIG_ADB_PMU
+       } else if (macintosh_config->adb_type == MAC_ADB_PB2) {
                pmu_shutdown();
 #endif
        }

@@ -519,9 +486,8 @@ void mac_reset(void)
                   macintosh_config->adb_type == MAC_ADB_CUDA) {
                cuda_restart();
 #endif
-#ifdef CONFIG_ADB_PMU68K
-       } else if (macintosh_config->adb_type == MAC_ADB_PB1
-               || macintosh_config->adb_type == MAC_ADB_PB2) {
+#ifdef CONFIG_ADB_PMU
+       } else if (macintosh_config->adb_type == MAC_ADB_PB2) {
                pmu_restart();
 #endif
        } else if (CPU_IS_030) {

The stability problem here is bigger than just pmu_restart() and 
pmu_shutdown(), so those hunks are insufficient. You need to prevent the 
via-pmu68k driver from loading in the first place and to drop all the 
PMU_68K_V1 cases.

But splitting this patch in that way creates potential merge conflicts, 
which is a hassle. E.g. this hunk:

-       ....
-       switch (macintosh_config->adb_type) {
-       case MAC_ADB_PB1:
-               pmu_kind = PMU_68K_V1;
-               break;
-       case MAC_ADB_PB2:
-               pmu_kind = PMU_68K_V2;
-               break;
-       default:
-               pmu_kind = PMU_UNKNOWN;
-               return -ENODEV;
-       }
-       ...

would get split over two patches.

The way I see it, having no PMU driver for PMU_68K_V1 machines is a bug. 
And loading any of the existing PMU drivers on that hardware is also a 
bug. These bugs are equivalent in that either one means you can't use the 
keyboard, trackpad etc. So there's no value in cherry-picking the other 
bug.

If you are using v4.17 on a PMU_68K_V1 machine, you probably already have 
CONFIG_ADB_PMU68K=n. With that config, here's nothing to be gained from 
bisecting these changes.

Does that make sense? Did I overlook other possible reason(s) to split up 
this patch?

--