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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Hi, Florian, Stefan and other Broadcom engineers, any thoughts about this series? Best regards, - Maíra On 16/08/26 11:05, Maíra Canal wrote: > vc4_reset() recovers a hung GPU by dropping the runtime PM usage count to > zero so that the V3D power domain goes down, and then taking it again. > Forcing the count to zero only works if the driver knows exactly how many > references it holds, which is why vc4 unconventionaly wraps every > pm_runtime_get_sync() call in a private refcount and mutex, making the > code cumbersome. > > The BCM2835 PM block has exposed a reset line for the V3D block since > commit 670c672608a1 ("soc: bcm: bcm2835-pm: Add support for power domains > under a new binding."), added for exactly this reason, but vc4 never > picked it up. This series switches vc4 over to it and drops the private > refcount, leaving vc4_v3d_pm_get/put() as plain runtime PM wrappers. > > The reset line is optional, so device trees that do not describe one keep > working: they get the driver-side recovery in vc4_irq_reset() while the > hardware is left untouched. Of the two in-tree platforms, > > 1. BCM2835 gains the property in PATCH 4. > 2. Cygnus has no V3D power domain to begin with, so the power-cycle > only ever gated its clock there. > > PATCH 1 is an independent cleanup. "brcm,vc4-v3d" was never documented > and was never used by any in-tree device tree, so it is a candidate for > removal on its own. It can be dropped from the series if it turns out > to be contentious. > > This series was tested on the Raspberry Pi 3B and 3B+. > > Best regards, > - Maíra > > --- > Maíra Canal (4): > drm/vc4: Drop the undocumented brcm,vc4-v3d compatible > dt-bindings: display: bcm2835-v3d: Add an optional reset line > drm/vc4: Use the reset controller to recover from a GPU hang > ARM: dts: bcm2835: Add the V3D reset line > > .../bindings/display/brcm,bcm2835-v3d.yaml | 3 ++ > arch/arm/boot/dts/broadcom/bcm2835-common.dtsi | 1 + > drivers/gpu/drm/vc4/vc4_drv.c | 1 - > drivers/gpu/drm/vc4/vc4_drv.h | 13 ++++--- > drivers/gpu/drm/vc4/vc4_gem.c | 40 +++++++++++++--------- > drivers/gpu/drm/vc4/vc4_irq.c | 7 ++-- > drivers/gpu/drm/vc4/vc4_v3d.c | 37 +++++++------------- > 7 files changed, 51 insertions(+), 51 deletions(-) > --- > base-commit: 09b47186a4164f3aaa3591313f80794443117342 > change-id: 20260812-vc4-reset-control-cddf3eb8a9e9 >