2010/6/17 Rafael J. Wysocki <rjw@xxxxxxx>: > On Wednesday, June 16, 2010, Alex Deucher wrote: >> On Wed, Jun 16, 2010 at 4:16 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: >> > On Wednesday, June 16, 2010, Ondrej Zary wrote: >> >> On Wednesday 16 June 2010, Rafael J. Wysocki wrote: >> >> > On Tuesday, June 15, 2010, Rafael J. Wysocki wrote: >> >> > > On Monday, June 14, 2010, Alex Deucher wrote: >> >> > > > On Mon, Jun 14, 2010 at 3:03 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: >> >> > > > > On Monday, June 14, 2010, Alex Deucher wrote: >> >> > > > >> On Mon, Jun 14, 2010 at 10:53 AM, Rafael J. Wysocki <rjw@xxxxxxx> >> >> wrote: >> >> > > > >> > Alex, Dave, >> >> > > > >> > >> >> > > > >> > I'm afraid hibernation is broken on all machines using radeon/KMS >> >> > > > >> > with r300 after commit ce8f53709bf440100cb9d31b1303291551cf517f >> >> > > > >> > (drm/radeon/kms/pm: rework power management). At least, I'm able >> >> > > > >> > to reproduce the symptom, which is that the machine hangs hard >> >> > > > >> > around the point where an image is created (probably during the >> >> > > > >> > device thaw phase), on two different boxes with r300 (the output >> >> > > > >> > of lspci from one of them is attached for reference, the other one >> >> > > > >> > is HP nx6325). >> >> > > > >> > >> >> > > > >> > Suspend to RAM appears to work fine at least on one of the >> >> > > > >> > affected boxes. >> >> > > > >> > >> >> > > > >> > Unfortunately, the commit above changes a lot of code and it's not >> >> > > > >> > too easy to figure out what's wrong with it and I didn't have the >> >> > > > >> > time to look more into details of this failure. However, it looks >> >> > > > >> > like you use .suspend() and .resume() callbacks as .freeze() and >> >> > > > >> > .thaw() which may not be 100% correct (in fact it looks like the >> >> > > > >> > "legacy" PCI suspend/resume is used, which is not recommended any >> >> > > > >> > more). >> >> > > > >> >> >> > > > >> Does it work any better after Dave's last drm pull request? >> >> > > > > >> >> > > > > Nope. The symptom is slightly different, though, because now it >> >> > > > > hangs after turning off the screen. >> >> > > > > >> >> > > > >> With the latest changes, pm should not be a factor unless it's >> >> > > > >> explicitly enabled via sysfs. >> >> > > > > >> >> > > > > Well, I guess the first pm patch changed more than just pm, then. >> >> > > > >> >> > > > Does this patch help? >> >> > > > http://lists.freedesktop.org/archives/dri-devel/2010-June/001314.html >> >> > > >> >> > > No, it doesn't. I try to hibernate, everything works to the point where >> >> > > the screen goes off and the box hangs (solid). Normally, it would turn >> >> > > the screen back on and continue with saving the image. >> >> > > >> >> > > But, since that happens with the patch above applied, I think it doesn't >> >> > > really pass the suspend phase (IOW, it probably hangs somewhere in the >> >> > > radeon's suspend routine). >> >> > >> >> > I've just verified that in fact hibernation works on HP nx6325 with >> >> > 2.6.35-rc3, but it takes about 55 sec. to suspend the graphics adapter in >> >> > the "freeze" phase. Surprisingly enough, during suspend to RAM it works >> >> > normally (as well as in the "poweroff" phase of hibernation). >> >> >> >> It takes 2 minutes on RV530: >> >> https://bugzilla.redhat.com/show_bug.cgi?id=586522 >> > >> > Well, my second affected box appears to hang somewhere in the radeon's suspend >> > routine. >> >> Does the attached patch help? > > It helps, but from what I can see in the code, it still has a few problems. > > First, the mutex around cancel_delayed_work() in radeon_pm_suspend() > doesn't really serve any purpose, because rdev->pm.pm_method cannot change > at this point and cancel_delayed_work() only tries to delete the work's timer. > Moreover, it doesn't prevent the work handler from running, in which case the > handler can do some wrong things and will rearm itself to do some more wrong > things going forward. So, I think it's better to wait for the handler to run in case it's > already been queued up and it should also be prevented from rearming itself in > that case. > > Second, in radeon_set_pm_method() the cancel_delayed_work() is not sufficient > to prevent the work handler from running and queing up itself for the next run > (the failure scenario is that cancel_delayed_work_sync() returns 0, so the > handler is run, it waits on the mutex and then rearms itself after the mutex > has been released), so it looks like cancel_delayed_work_sync() > should be used to make sure it's not going to run again, but calling > that cancel_delayed_work_sync() from under the mutex is not a good idea. > > Finally, there's a potential deadlock in radeon_pm_fini(), where > cancel_delayed_work_sync() is called under rdev->pm.mutex, but the > work handler tries to acquire the same mutex (if it wins the race). > > So, I think something like the appended patch is needed. > Looks reasonable. Does it fix the suspend issue? Alex > Rafael > > > Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx> > --- > drivers/gpu/drm/radeon/radeon.h | 3 +- > drivers/gpu/drm/radeon/radeon_pm.c | 41 ++++++++++++++++++++++++++++++------- > 2 files changed, 36 insertions(+), 8 deletions(-) > > Index: linux-2.6/drivers/gpu/drm/radeon/radeon_pm.c > =================================================================== > --- linux-2.6.orig/drivers/gpu/drm/radeon/radeon_pm.c > +++ linux-2.6/drivers/gpu/drm/radeon/radeon_pm.c > @@ -397,13 +397,20 @@ static ssize_t radeon_set_pm_method(stru > rdev->pm.dynpm_planned_action = DYNPM_ACTION_DEFAULT; > mutex_unlock(&rdev->pm.mutex); > } else if (strncmp("profile", buf, strlen("profile")) == 0) { > + bool flush_wq = false; > + > mutex_lock(&rdev->pm.mutex); > - rdev->pm.pm_method = PM_METHOD_PROFILE; > + if (rdev->pm.pm_method == PM_METHOD_DYNPM) { > + cancel_delayed_work(&rdev->pm.dynpm_idle_work); > + flush_wq = true; > + } > /* disable dynpm */ > rdev->pm.dynpm_state = DYNPM_STATE_DISABLED; > rdev->pm.dynpm_planned_action = DYNPM_ACTION_NONE; > - cancel_delayed_work(&rdev->pm.dynpm_idle_work); > + rdev->pm.pm_method = PM_METHOD_PROFILE; > mutex_unlock(&rdev->pm.mutex); > + if (flush_wq) > + flush_workqueue(rdev->wq); > } else { > DRM_ERROR("invalid power method!\n"); > goto fail; > @@ -418,9 +425,18 @@ static DEVICE_ATTR(power_method, S_IRUGO > > void radeon_pm_suspend(struct radeon_device *rdev) > { > + bool flush_wq = false; > + > mutex_lock(&rdev->pm.mutex); > - cancel_delayed_work(&rdev->pm.dynpm_idle_work); > + if (rdev->pm.pm_method == PM_METHOD_DYNPM) { > + cancel_delayed_work(&rdev->pm.dynpm_idle_work); > + if (rdev->pm.dynpm_state == DYNPM_STATE_ACTIVE) > + rdev->pm.dynpm_state = DYNPM_STATE_SUSPENDED; > + flush_wq = true; > + } > mutex_unlock(&rdev->pm.mutex); > + if (flush_wq) > + flush_workqueue(rdev->wq); > } > > void radeon_pm_resume(struct radeon_device *rdev) > @@ -432,6 +448,12 @@ void radeon_pm_resume(struct radeon_devi > rdev->pm.current_sclk = rdev->clock.default_sclk; > rdev->pm.current_mclk = rdev->clock.default_mclk; > rdev->pm.current_vddc = rdev->pm.power_state[rdev->pm.default_power_state_index].clock_info[0].voltage.voltage; > + if (rdev->pm.pm_method == PM_METHOD_DYNPM > + && rdev->pm.dynpm_state == DYNPM_STATE_SUSPENDED) { > + rdev->pm.dynpm_state = DYNPM_STATE_ACTIVE; > + queue_delayed_work(rdev->wq, &rdev->pm.dynpm_idle_work, > + msecs_to_jiffies(RADEON_IDLE_LOOP_MS)); > + } > mutex_unlock(&rdev->pm.mutex); > radeon_pm_compute_clocks(rdev); > } > @@ -486,6 +508,8 @@ int radeon_pm_init(struct radeon_device > void radeon_pm_fini(struct radeon_device *rdev) > { > if (rdev->pm.num_power_states > 1) { > + bool flush_wq = false; > + > mutex_lock(&rdev->pm.mutex); > if (rdev->pm.pm_method == PM_METHOD_PROFILE) { > rdev->pm.profile = PM_PROFILE_DEFAULT; > @@ -493,13 +517,16 @@ void radeon_pm_fini(struct radeon_device > radeon_pm_set_clocks(rdev); > } else if (rdev->pm.pm_method == PM_METHOD_DYNPM) { > /* cancel work */ > - cancel_delayed_work_sync(&rdev->pm.dynpm_idle_work); > + cancel_delayed_work(&rdev->pm.dynpm_idle_work); > + flush_wq = true; > /* reset default clocks */ > rdev->pm.dynpm_state = DYNPM_STATE_DISABLED; > rdev->pm.dynpm_planned_action = DYNPM_ACTION_DEFAULT; > radeon_pm_set_clocks(rdev); > } > mutex_unlock(&rdev->pm.mutex); > + if (flush_wq) > + flush_workqueue(rdev->wq); > > device_remove_file(rdev->dev, &dev_attr_power_profile); > device_remove_file(rdev->dev, &dev_attr_power_method); > @@ -720,12 +747,12 @@ static void radeon_dynpm_idle_work_handl > radeon_pm_get_dynpm_state(rdev); > radeon_pm_set_clocks(rdev); > } > + > + queue_delayed_work(rdev->wq, &rdev->pm.dynpm_idle_work, > + msecs_to_jiffies(RADEON_IDLE_LOOP_MS)); > } > mutex_unlock(&rdev->pm.mutex); > ttm_bo_unlock_delayed_workqueue(&rdev->mman.bdev, resched); > - > - queue_delayed_work(rdev->wq, &rdev->pm.dynpm_idle_work, > - msecs_to_jiffies(RADEON_IDLE_LOOP_MS)); > } > > /* > Index: linux-2.6/drivers/gpu/drm/radeon/radeon.h > =================================================================== > --- linux-2.6.orig/drivers/gpu/drm/radeon/radeon.h > +++ linux-2.6/drivers/gpu/drm/radeon/radeon.h > @@ -619,7 +619,8 @@ enum radeon_dynpm_state { > DYNPM_STATE_DISABLED, > DYNPM_STATE_MINIMUM, > DYNPM_STATE_PAUSED, > - DYNPM_STATE_ACTIVE > + DYNPM_STATE_ACTIVE, > + DYNPM_STATE_SUSPENDED, > }; > enum radeon_dynpm_action { > DYNPM_ACTION_NONE, > _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
