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-rw-r--r--drivers/macintosh/smu.c25
1 files changed, 24 insertions, 1 deletions
diff --git a/drivers/macintosh/smu.c b/drivers/macintosh/smu.c
index 8ba49385c3f..77ad192962c 100644
--- a/drivers/macintosh/smu.c
+++ b/drivers/macintosh/smu.c
@@ -85,6 +85,7 @@ struct smu_device {
u32 cmd_buf_abs; /* command buffer absolute */
struct list_head cmd_list;
struct smu_cmd *cmd_cur; /* pending command */
+ int broken_nap;
struct list_head cmd_i2c_list;
struct smu_i2c_cmd *cmd_i2c_cur; /* pending i2c command */
struct timer_list i2c_timer;
@@ -135,6 +136,19 @@ static void smu_start_cmd(void)
fend = faddr + smu->cmd_buf->length + 2;
flush_inval_dcache_range(faddr, fend);
+
+ /* We also disable NAP mode for the duration of the command
+ * on U3 based machines.
+ * This is slightly racy as it can be written back to 1 by a sysctl
+ * but that never happens in practice. There seem to be an issue with
+ * U3 based machines such as the iMac G5 where napping for the
+ * whole duration of the command prevents the SMU from fetching it
+ * from memory. This might be related to the strange i2c based
+ * mechanism the SMU uses to access memory.
+ */
+ if (smu->broken_nap)
+ powersave_nap = 0;
+
/* This isn't exactly a DMA mapping here, I suspect
* the SMU is actually communicating with us via i2c to the
* northbridge or the CPU to access RAM.
@@ -211,6 +225,10 @@ static irqreturn_t smu_db_intr(int irq, void *arg)
misc = cmd->misc;
mb();
cmd->status = rc;
+
+ /* Re-enable NAP mode */
+ if (smu->broken_nap)
+ powersave_nap = 1;
bail:
/* Start next command if any */
smu_start_cmd();
@@ -461,7 +479,7 @@ int __init smu_init (void)
if (np == NULL)
return -ENODEV;
- printk(KERN_INFO "SMU driver %s %s\n", VERSION, AUTHOR);
+ printk(KERN_INFO "SMU: Driver %s %s\n", VERSION, AUTHOR);
if (smu_cmdbuf_abs == 0) {
printk(KERN_ERR "SMU: Command buffer not allocated !\n");
@@ -533,6 +551,11 @@ int __init smu_init (void)
goto fail;
}
+ /* U3 has an issue with NAP mode when issuing SMU commands */
+ smu->broken_nap = pmac_get_uninorth_variant() < 4;
+ if (smu->broken_nap)
+ printk(KERN_INFO "SMU: using NAP mode workaround\n");
+
sys_ctrler = SYS_CTRLER_SMU;
return 0;