On Thu, Apr 18, 2024 at 06:37:56PM -0400, Rodrigo Vivi wrote:
> In the past, the noresume function was used by the GEM code to ensure
> wakelocks were held and bump its usage. This is no longer the case
> and this function was totally unused until it started to be used again
> by display with commit 77e619a82fc3 ("drm/i915/display: convert inner
> wakeref get towards get_if_in_use")
>
> However, on the display code, most of the callers are using the
> raw wakeref, rather then the wakelock version. What caused a
> major regression caught by CI.
>
> Another option to this patch is to go with the original plan and
> use the get_if_in_use variant in the display code, what is enough
> to fulfil our needs. Then, an extra patch to delete the unused
> _noresume variant.
>
> v2: Keep grabbing wakelock but only assert for wakeref. (Imre)
>
> Cc: Imre Deak <imre.deak@xxxxxxxxx>
> Cc: Francois Dugast <francois.dugast@xxxxxxxxx>
> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> Fixes: 77e619a82fc3 ("drm/i915/display: convert inner wakeref get towards get_if_in_use")
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/10875
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Reviewed-by: Imre Deak <imre.deak@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_display_power.c | 6 ------
> drivers/gpu/drm/i915/intel_runtime_pm.c | 14 +++++---------
> 2 files changed, 5 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c b/drivers/gpu/drm/i915/display/intel_display_power.c
> index 048943d0a881..03dc7edcc443 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_power.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_power.c
> @@ -640,12 +640,6 @@ release_async_put_domains(struct i915_power_domains *power_domains,
> enum intel_display_power_domain domain;
> intel_wakeref_t wakeref;
>
> - /*
> - * The caller must hold already raw wakeref, upgrade that to a proper
> - * wakeref to make the state checker happy about the HW access during
> - * power well disabling.
> - */
> - assert_rpm_raw_wakeref_held(rpm);
> wakeref = intel_runtime_pm_get_noresume(rpm);
>
> for_each_power_domain(domain, mask) {
> diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
> index d4e844128826..2d0647aca964 100644
> --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> @@ -272,15 +272,11 @@ intel_wakeref_t intel_runtime_pm_get_if_active(struct intel_runtime_pm *rpm)
> * intel_runtime_pm_get_noresume - grab a runtime pm reference
> * @rpm: the intel_runtime_pm structure
> *
> - * This function grabs a device-level runtime pm reference (mostly used for GEM
> - * code to ensure the GTT or GT is on).
> + * This function grabs a device-level runtime pm reference.
> *
> - * It will _not_ power up the device but instead only check that it's powered
> - * on. Therefore it is only valid to call this functions from contexts where
> - * the device is known to be powered up and where trying to power it up would
> - * result in hilarity and deadlocks. That pretty much means only the system
> - * suspend/resume code where this is used to grab runtime pm references for
> - * delayed setup down in work items.
> + * It will _not_ resume the device but instead only get an extra wakeref.
> + * Therefore it is only valid to call this functions from contexts where
> + * the device is known to be active and with another wakeref previously hold.
> *
> * Any runtime pm reference obtained by this function must have a symmetric
> * call to intel_runtime_pm_put() to release the reference again.
> @@ -289,7 +285,7 @@ intel_wakeref_t intel_runtime_pm_get_if_active(struct intel_runtime_pm *rpm)
> */
> intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm)
> {
> - assert_rpm_wakelock_held(rpm);
> + assert_rpm_raw_wakeref_held(rpm);
> pm_runtime_get_noresume(rpm->kdev);
>
> intel_runtime_pm_acquire(rpm, true);
> --
> 2.44.0
>
