On Mon, 2013-03-11 at 11:42 +0800, Aaron Lu wrote: > Hi all, > > I've seen some reports on STANDBY IMMEDIATE failed on NVIDIA MCP5x > controllers when system goes to suspend(this command is sent by scsi sd > driver on system suspend as a SCSI STOP command, which is translated to > STANDBY IMMEDIATE ATA command). I've no idea of why this happened, so > I wrote this email in hope of getting some new idea. > > The related bug report: > https://bugzilla.kernel.org/show_bug.cgi?id=48951 > > And google search showed that Peter reported a similar problem here: > http://marc.info/?l=linux-ide&m=133534061316338&w=2 > > And bladud has found that, disable asyn suspend for the scsi target > device can work around this problem. > > Please feel free to suggest what can possibly be the cause, thanks. I sometimes despair of people getting PM stuff right. What on earth is the point of refusing to suspend if the disk refuses to stop? In theory it gives the device more time to park its head, but almost no modern drive requires this. The next action suspend will take (if allowed) is to power down peripherals which will forcibly stop the device. The stop request is purely informational for the device. If it ignores it, then the bigger hammer still works. You really need to discriminate better between conditions we should and shouldn't care about for suspend. so in sd_suspend, we definitely care if we can't flush the cache of a write back device because the power off could lose data. We don't really care if the disk says I can't stop, so this is probably the correct fix. James --- diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 7992635..384b621d 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -3079,7 +3079,11 @@ static int sd_suspend(struct device *dev) if (sdkp->device->manage_start_stop) { sd_printk(KERN_NOTICE, sdkp, "Stopping disk\n"); - ret = sd_start_stop_device(sdkp, 0); + /* + * this is informational for the disk we're going to power it + * off anyway, so don't bother about the return status + */ + sd_start_stop_device(sdkp, 0); } done: -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
