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Message-ID: <09151ff9-ff2a-4d3d-9ee1-b6f30b729fe6@arm.com>
Date: Wed, 14 Jan 2026 16:07:00 +0000
From: Steven Price <steven.price@....com>
To: Nicolas Frattaroli <nicolas.frattaroli@...labora.com>,
Boris Brezillon <boris.brezillon@...labora.com>,
Liviu Dudau <liviu.dudau@....com>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
Chia-I Wu <olvaffe@...il.com>, Karunika Choo <karunika.choo@....com>
Cc: kernel@...labora.com, linux-kernel@...r.kernel.org,
dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH v8 1/4] drm/panthor: Rework panthor_irq::suspended into
panthor_irq::state
On 12/01/2026 14:37, Nicolas Frattaroli wrote:
> To deal with the threaded interrupt handler and a suspend action
> overlapping, the boolean panthor_irq::suspended is not sufficient.
>
> Rework it into taking several different values depending on the current
> state, and check it and set it within the IRQ helper functions.
>
> Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
There are some unwanted changes in this patch. We want to keep it simple
so it does exactly what the changelog says. See below.
> ---
> drivers/gpu/drm/panthor/panthor_device.h | 40 +++++++++++++++++++++++++-------
> 1 file changed, 31 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_device.h b/drivers/gpu/drm/panthor/panthor_device.h
> index f35e52b9546a..424f6cd1a814 100644
> --- a/drivers/gpu/drm/panthor/panthor_device.h
> +++ b/drivers/gpu/drm/panthor/panthor_device.h
> @@ -61,6 +61,17 @@ enum panthor_device_pm_state {
> PANTHOR_DEVICE_PM_STATE_SUSPENDING,
> };
>
> +enum panthor_irq_state {
> + /** @PANTHOR_IRQ_STATE_ACTIVE: IRQ is active and ready to process events. */
> + PANTHOR_IRQ_STATE_ACTIVE = 0,
> + /** @PANTHOR_IRQ_STATE_PROCESSING: IRQ is currently processing events. */
> + PANTHOR_IRQ_STATE_PROCESSING,
> + /** @PANTHOR_IRQ_STATE_SUSPENDED: IRQ is suspended. */
> + PANTHOR_IRQ_STATE_SUSPENDED,
> + /** @PANTHOR_IRQ_STATE_SUSPENDING: IRQ is being suspended. */
> + PANTHOR_IRQ_STATE_SUSPENDING,
> +};
> +
> /**
> * struct panthor_irq - IRQ data
> *
> @@ -76,8 +87,8 @@ struct panthor_irq {
> /** @mask: Current mask being applied to xxx_INT_MASK. */
> u32 mask;
>
> - /** @suspended: Set to true when the IRQ is suspended. */
> - atomic_t suspended;
> + /** @state: one of &enum panthor_irq_state reflecting the current state. */
> + atomic_t state;
> };
>
> /**
> @@ -409,8 +420,10 @@ static irqreturn_t panthor_ ## __name ## _irq_raw_handler(int irq, void *data)
> { \
> struct panthor_irq *pirq = data; \
> struct panthor_device *ptdev = pirq->ptdev; \
> + enum panthor_irq_state state; \
> \
> - if (atomic_read(&pirq->suspended)) \
> + state = atomic_read(&pirq->state); \
> + if (state == PANTHOR_IRQ_STATE_SUSPENDED || state == PANTHOR_IRQ_STATE_SUSPENDING) \
> return IRQ_NONE; \
> if (!gpu_read(ptdev, __reg_prefix ## _INT_STAT)) \
> return IRQ_NONE; \
> @@ -423,8 +436,11 @@ static irqreturn_t panthor_ ## __name ## _irq_threaded_handler(int irq, void *da
> { \
> struct panthor_irq *pirq = data; \
> struct panthor_device *ptdev = pirq->ptdev; \
> + enum panthor_irq_state state; \
> irqreturn_t ret = IRQ_NONE; \
> \
> + atomic_cmpxchg(&pirq->state, PANTHOR_IRQ_STATE_ACTIVE, PANTHOR_IRQ_STATE_PROCESSING); \
> + \
> while (true) { \
> u32 status = gpu_read(ptdev, __reg_prefix ## _INT_RAWSTAT) & pirq->mask; \
> \
> @@ -435,8 +451,13 @@ static irqreturn_t panthor_ ## __name ## _irq_threaded_handler(int irq, void *da
> ret = IRQ_HANDLED; \
> } \
> \
> - if (!atomic_read(&pirq->suspended)) \
> - gpu_write(ptdev, __reg_prefix ## _INT_MASK, pirq->mask); \
> + state = atomic_read(&pirq->state); \
> + if (state != PANTHOR_IRQ_STATE_SUSPENDED && state != PANTHOR_IRQ_STATE_SUSPENDING) { \
> + /* Only restore the bits that were used and are still enabled */ \
> + gpu_write(ptdev, __reg_prefix ## _INT_MASK, \
> + gpu_read(ptdev, __reg_prefix ## _INT_MASK) | (mask & pirq->mask)); \
This change to read the _INT_MASK and mask pirq->mask with 'mask'
shouldn't be part of this patch.
> + atomic_set(&pirq->state, PANTHOR_IRQ_STATE_ACTIVE); \
> + } \
> \
> return ret; \
> } \
> @@ -445,16 +466,17 @@ static inline void panthor_ ## __name ## _irq_suspend(struct panthor_irq *pirq)
> { \
> pirq->mask = 0; \
> gpu_write(pirq->ptdev, __reg_prefix ## _INT_MASK, 0); \
> + atomic_set(&pirq->state, PANTHOR_IRQ_STATE_SUSPENDING); \
> synchronize_irq(pirq->irq); \
> - atomic_set(&pirq->suspended, true); \
> + atomic_set(&pirq->state, PANTHOR_IRQ_STATE_SUSPENDED); \
> } \
> \
> static inline void panthor_ ## __name ## _irq_resume(struct panthor_irq *pirq, u32 mask) \
> { \
> - atomic_set(&pirq->suspended, false); \
> pirq->mask = mask; \
> - gpu_write(pirq->ptdev, __reg_prefix ## _INT_CLEAR, mask); \
> - gpu_write(pirq->ptdev, __reg_prefix ## _INT_MASK, mask); \
> + atomic_set(&pirq->state, PANTHOR_IRQ_STATE_ACTIVE); \
> + gpu_write(pirq->ptdev, __reg_prefix ## _INT_CLEAR, pirq->mask); \
> + gpu_write(pirq->ptdev, __reg_prefix ## _INT_MASK, pirq->mask); \
Here the change from using the local 'mask' to 'pirq->mask' is
unrelated. It belongs in the next patch where 'mask' is being removed.
But otherwise this looks good to me.
Thanks,
Steve
> } \
> \
> static int panthor_request_ ## __name ## _irq(struct panthor_device *ptdev, \
>
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