Bug#452909: [PATCH] Support PMU Suspend Detection

[Matthew William Cox]

On Sat, Feb 02, 2008 at 12:49:38AM +0100, Michael Biebl wrote:
> That's not quite correct. Upstream is also broken, as pm-is-supported  
> doesn't recognize pmu support.

In the interests of getting this fixed, I dug into pm-pmu.c and added
the ability to query the PMU to detect if suspending is supported. I've
tested it by manually building pm-pmu and checking the suspend and
can-suspend functions:

> if sudo ./pm-pmu --can-suspend; then sudo ./pm-pmu --suspend; fi

This successfully suspends my Powerbook G4. I've tested it against
linux-image-2.6.22-3-powerpc, and against linux-image-2.6.24-1-powerpc.

Hopefully we can integrate this into pm-utils, and get this bug resolved.
My debian-fu isn't developed enough to understand how to dig into this
package fix the rest of it, but I am interested in doing the work. I'll
have to go read up on the debian packaging utilities before I continue.
In the mean time, if somebody else can use my patch to zap this bug,
please do.

Cheers,
Matthew

diff -ur pm-utils-0.99.2-orig/src/pm-pmu.c pm-utils-0.99.2/src/pm-pmu.c
--- pm-utils-0.99.2-orig/src/pm-pmu.c	2006-08-08 11:17:28.000000000 -0400
+++ pm-utils-0.99.2/src/pm-pmu.c	2008-02-01 21:12:07.000000000 -0500
@@ -53,10 +53,20 @@
     return 0;
 }
 
+static int
+pmu_can_sleep(const int fd)
+{
+    unsigned long cap = 0;
+    if (ioctl(fd, PMU_IOC_CAN_SLEEP, &cap) < 0 || cap != 1)
+        return 1;
+
+    return 0;
+}
+
 static inline int
 print_usage(FILE *output, int retval)
 {
-    fprintf(output, "usage: pm-pmu --suspend\n");
+    fprintf(output, "usage: pm-pmu [--suspend | --can-suspend]\n");
     return retval;
 }
 
@@ -80,6 +90,17 @@
         ret = pmu_sleep(fd);
         close(fd);
         return ret;
+    } else if (!strcmp(argv[1], "--can-suspend")) {
+        int fd, ret;
+        /* Need RDRW perm on pmu to issue PMU_IOC_CAN_SLEEP */
+        if ((fd = open ("/dev/pmu", O_RDWR)) < 0) {
+            perror("open");
+            return 1;
+        }
+
+        ret = pmu_can_sleep(fd);
+        close(fd);
+        return ret;
     }
     
     return print_usage(stderr, 1);

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