From: Chia-I Wu <olvaffe@gmail.com>
To: Boris Brezillon <boris.brezillon@collabora.com>
Cc: Steven Price <steven.price@arm.com>,
Liviu Dudau <liviu.dudau@arm.com>,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Maxime Ripard <mripard@kernel.org>,
Thomas Zimmermann <tzimmermann@suse.de>,
David Airlie <airlied@gmail.com>, Simona Vetter <simona@ffwll.ch>,
dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 08/11] drm/panthor: Automatically enable interrupts in panthor_fw_wait_acks()
Date: Tue, 12 May 2026 14:55:30 -0700 [thread overview]
Message-ID: <CAPaKu7Sx85JpFFJ_4w3mZ6_OPkCHDqp68Uo+RbeYx=5v03vdww@mail.gmail.com> (raw)
In-Reply-To: <20260512-panthor-signal-from-irq-v2-8-95c614a739cb@collabora.com>
On Tue, May 12, 2026 at 4:54 AM Boris Brezillon
<boris.brezillon@collabora.com> wrote:
>
> Rather than assuming an interrupt is always expected for request
> acks, temporarily enable the relevant interrupts when the polling-wait
> failed. This should hopefully reduce the number of interrupts the CPU
> has to process.
>
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
WIth minor comments below, Reviewed-by: Chia-I Wu <olvaffe@gmail.com>
> ---
> drivers/gpu/drm/panthor/panthor_fw.c | 34 +++++++++++++++++++--------------
> drivers/gpu/drm/panthor/panthor_sched.c | 5 +++--
> 2 files changed, 23 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_fw.c b/drivers/gpu/drm/panthor/panthor_fw.c
> index 8239a6951569..f5e0ceca4130 100644
> --- a/drivers/gpu/drm/panthor/panthor_fw.c
> +++ b/drivers/gpu/drm/panthor/panthor_fw.c
> @@ -1039,16 +1039,10 @@ static void panthor_fw_init_global_iface(struct panthor_device *ptdev)
> glb_iface->input->progress_timer = PROGRESS_TIMEOUT_CYCLES >> PROGRESS_TIMEOUT_SCALE_SHIFT;
> glb_iface->input->idle_timer = panthor_fw_conv_timeout(ptdev, IDLE_HYSTERESIS_US);
>
> - /* Enable interrupts we care about. */
> - glb_iface->input->ack_irq_mask = GLB_CFG_ALLOC_EN |
> - GLB_PING |
> - GLB_CFG_PROGRESS_TIMER |
> - GLB_CFG_POWEROFF_TIMER |
> - GLB_IDLE_EN |
> - GLB_IDLE;
> -
> - if (panthor_fw_has_glb_state(ptdev))
> - glb_iface->input->ack_irq_mask |= GLB_STATE_MASK;
> + /* Enable interrupts for asynchronous events that are not
> + * triggered by request acks.
> + */
> + glb_iface->input->ack_irq_mask = GLB_IDLE;
We should static_assert or & with GLB_EVT_MASK. Same for CSG and CS.
>
> panthor_fw_update_reqs(glb_iface, req, GLB_IDLE_EN | GLB_COUNTER_EN,
> GLB_IDLE_EN | GLB_COUNTER_EN);
> @@ -1318,8 +1312,8 @@ void panthor_fw_unplug(struct panthor_device *ptdev)
> * Return: 0 on success, -ETIMEDOUT otherwise.
> */
> static int panthor_fw_wait_acks(const u32 *req_ptr, const u32 *ack_ptr,
> - wait_queue_head_t *wq,
> - u32 req_mask, u32 *acked,
> + u32 *ack_irq_mask_ptr, spinlock_t *lock,
> + wait_queue_head_t *wq, u32 req_mask, u32 *acked,
> u32 timeout_ms)
> {
> u32 ack, req = READ_ONCE(*req_ptr) & req_mask;
> @@ -1334,8 +1328,16 @@ static int panthor_fw_wait_acks(const u32 *req_ptr, const u32 *ack_ptr,
> if (!ret)
> return 0;
>
> - if (wait_event_timeout(*wq, (READ_ONCE(*ack_ptr) & req_mask) == req,
> - msecs_to_jiffies(timeout_ms)))
> + scoped_guard(spinlock_irqsave, lock)
> + *ack_irq_mask_ptr |= req_mask;
> +
> + ret = wait_event_timeout(*wq, (READ_ONCE(*ack_ptr) & req_mask) == req,
> + msecs_to_jiffies(timeout_ms));
> +
> + scoped_guard(spinlock_irqsave, lock)
> + *ack_irq_mask_ptr &= ~req_mask;
We should add a comment saying that this is safe because
{GLB,CSG,CS}_REQ_MASK and {GLB,CSG,CS}_EVT_MASK are disjoint, and thus
req_mask and ack_irq_mask are disjoint.
> +
> + if (ret)
> return 0;
>
> /* Check one last time, in case we were not woken up for some reason. */
> @@ -1369,6 +1371,8 @@ int panthor_fw_glb_wait_acks(struct panthor_device *ptdev,
>
> return panthor_fw_wait_acks(&glb_iface->input->req,
> &glb_iface->output->ack,
> + &glb_iface->input->ack_irq_mask,
> + &glb_iface->lock,
> &ptdev->fw->req_waitqueue,
> req_mask, acked, timeout_ms);
> }
> @@ -1395,6 +1399,8 @@ int panthor_fw_csg_wait_acks(struct panthor_device *ptdev, u32 csg_slot,
>
> ret = panthor_fw_wait_acks(&csg_iface->input->req,
> &csg_iface->output->ack,
> + &csg_iface->input->ack_irq_mask,
> + &csg_iface->lock,
> &ptdev->fw->req_waitqueue,
> req_mask, acked, timeout_ms);
>
> diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c
> index 6c5ba747ae45..a9124bcc7de6 100644
> --- a/drivers/gpu/drm/panthor/panthor_sched.c
> +++ b/drivers/gpu/drm/panthor/panthor_sched.c
> @@ -1110,7 +1110,7 @@ cs_slot_prog_locked(struct panthor_device *ptdev, u32 csg_id, u32 cs_id)
> cs_iface->input->ringbuf_output = queue->iface.output_fw_va;
> cs_iface->input->config = CS_CONFIG_PRIORITY(queue->priority) |
> CS_CONFIG_DOORBELL(queue->doorbell_id);
> - cs_iface->input->ack_irq_mask = ~0;
> + cs_iface->input->ack_irq_mask = CS_FATAL | CS_FAULT | CS_TILER_OOM;
> panthor_fw_update_reqs(cs_iface, req,
> CS_IDLE_SYNC_WAIT |
> CS_IDLE_EMPTY |
> @@ -1378,7 +1378,8 @@ csg_slot_prog_locked(struct panthor_device *ptdev, u32 csg_id, u32 priority)
> csg_iface->input->protm_suspend_buf = 0;
> }
>
> - csg_iface->input->ack_irq_mask = ~0;
> + csg_iface->input->ack_irq_mask = CSG_SYNC_UPDATE | CSG_IDLE |
> + CSG_PROGRESS_TIMER_EVENT;
> panthor_fw_toggle_reqs(csg_iface, doorbell_req, doorbell_ack, queue_mask);
> return 0;
> }
>
> --
> 2.54.0
>
On Tue, May 12, 2026 at 4:54 AM Boris Brezillon
<boris.brezillon@collabora.com> wrote:
>
> Rather than assuming an interrupt is always expected for request
> acks, temporarily enable the relevant interrupts when the polling-wait
> failed. This should hopefully reduce the number of interrupts the CPU
> has to process.
>
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> ---
> drivers/gpu/drm/panthor/panthor_fw.c | 34 +++++++++++++++++++--------------
> drivers/gpu/drm/panthor/panthor_sched.c | 5 +++--
> 2 files changed, 23 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_fw.c b/drivers/gpu/drm/panthor/panthor_fw.c
> index 8239a6951569..f5e0ceca4130 100644
> --- a/drivers/gpu/drm/panthor/panthor_fw.c
> +++ b/drivers/gpu/drm/panthor/panthor_fw.c
> @@ -1039,16 +1039,10 @@ static void panthor_fw_init_global_iface(struct panthor_device *ptdev)
> glb_iface->input->progress_timer = PROGRESS_TIMEOUT_CYCLES >> PROGRESS_TIMEOUT_SCALE_SHIFT;
> glb_iface->input->idle_timer = panthor_fw_conv_timeout(ptdev, IDLE_HYSTERESIS_US);
>
> - /* Enable interrupts we care about. */
> - glb_iface->input->ack_irq_mask = GLB_CFG_ALLOC_EN |
> - GLB_PING |
> - GLB_CFG_PROGRESS_TIMER |
> - GLB_CFG_POWEROFF_TIMER |
> - GLB_IDLE_EN |
> - GLB_IDLE;
> -
> - if (panthor_fw_has_glb_state(ptdev))
> - glb_iface->input->ack_irq_mask |= GLB_STATE_MASK;
> + /* Enable interrupts for asynchronous events that are not
> + * triggered by request acks.
> + */
> + glb_iface->input->ack_irq_mask = GLB_IDLE;
>
> panthor_fw_update_reqs(glb_iface, req, GLB_IDLE_EN | GLB_COUNTER_EN,
> GLB_IDLE_EN | GLB_COUNTER_EN);
> @@ -1318,8 +1312,8 @@ void panthor_fw_unplug(struct panthor_device *ptdev)
> * Return: 0 on success, -ETIMEDOUT otherwise.
> */
> static int panthor_fw_wait_acks(const u32 *req_ptr, const u32 *ack_ptr,
> - wait_queue_head_t *wq,
> - u32 req_mask, u32 *acked,
> + u32 *ack_irq_mask_ptr, spinlock_t *lock,
> + wait_queue_head_t *wq, u32 req_mask, u32 *acked,
> u32 timeout_ms)
> {
> u32 ack, req = READ_ONCE(*req_ptr) & req_mask;
> @@ -1334,8 +1328,16 @@ static int panthor_fw_wait_acks(const u32 *req_ptr, const u32 *ack_ptr,
> if (!ret)
> return 0;
>
> - if (wait_event_timeout(*wq, (READ_ONCE(*ack_ptr) & req_mask) == req,
> - msecs_to_jiffies(timeout_ms)))
> + scoped_guard(spinlock_irqsave, lock)
> + *ack_irq_mask_ptr |= req_mask;
> +
> + ret = wait_event_timeout(*wq, (READ_ONCE(*ack_ptr) & req_mask) == req,
> + msecs_to_jiffies(timeout_ms));
> +
> + scoped_guard(spinlock_irqsave, lock)
> + *ack_irq_mask_ptr &= ~req_mask;
> +
> + if (ret)
> return 0;
>
> /* Check one last time, in case we were not woken up for some reason. */
> @@ -1369,6 +1371,8 @@ int panthor_fw_glb_wait_acks(struct panthor_device *ptdev,
>
> return panthor_fw_wait_acks(&glb_iface->input->req,
> &glb_iface->output->ack,
> + &glb_iface->input->ack_irq_mask,
> + &glb_iface->lock,
> &ptdev->fw->req_waitqueue,
> req_mask, acked, timeout_ms);
> }
> @@ -1395,6 +1399,8 @@ int panthor_fw_csg_wait_acks(struct panthor_device *ptdev, u32 csg_slot,
>
> ret = panthor_fw_wait_acks(&csg_iface->input->req,
> &csg_iface->output->ack,
> + &csg_iface->input->ack_irq_mask,
> + &csg_iface->lock,
> &ptdev->fw->req_waitqueue,
> req_mask, acked, timeout_ms);
>
> diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c
> index 6c5ba747ae45..a9124bcc7de6 100644
> --- a/drivers/gpu/drm/panthor/panthor_sched.c
> +++ b/drivers/gpu/drm/panthor/panthor_sched.c
> @@ -1110,7 +1110,7 @@ cs_slot_prog_locked(struct panthor_device *ptdev, u32 csg_id, u32 cs_id)
> cs_iface->input->ringbuf_output = queue->iface.output_fw_va;
> cs_iface->input->config = CS_CONFIG_PRIORITY(queue->priority) |
> CS_CONFIG_DOORBELL(queue->doorbell_id);
> - cs_iface->input->ack_irq_mask = ~0;
> + cs_iface->input->ack_irq_mask = CS_FATAL | CS_FAULT | CS_TILER_OOM;
> panthor_fw_update_reqs(cs_iface, req,
> CS_IDLE_SYNC_WAIT |
> CS_IDLE_EMPTY |
> @@ -1378,7 +1378,8 @@ csg_slot_prog_locked(struct panthor_device *ptdev, u32 csg_id, u32 priority)
> csg_iface->input->protm_suspend_buf = 0;
> }
>
> - csg_iface->input->ack_irq_mask = ~0;
> + csg_iface->input->ack_irq_mask = CSG_SYNC_UPDATE | CSG_IDLE |
> + CSG_PROGRESS_TIMER_EVENT;
> panthor_fw_toggle_reqs(csg_iface, doorbell_req, doorbell_ack, queue_mask);
> return 0;
> }
>
> --
> 2.54.0
>
next prev parent reply other threads:[~2026-05-12 21:55 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-12 11:37 [PATCH v2 00/11] drm/panthor: Reduce dma_fence signalling latency Boris Brezillon
2026-05-12 11:37 ` [PATCH v2 01/11] drm/panthor: Make panthor_irq::state a non-atomic field Boris Brezillon
2026-05-12 18:40 ` Chia-I Wu
2026-05-16 3:32 ` Claude review: " Claude Code Review Bot
2026-05-12 11:37 ` [PATCH v2 02/11] drm/panthor: Move the register accessors before the IRQ helpers Boris Brezillon
2026-05-12 18:41 ` Chia-I Wu
2026-05-16 3:32 ` Claude review: " Claude Code Review Bot
2026-05-12 11:37 ` [PATCH v2 03/11] drm/panthor: Replace the panthor_irq macro machinery by inline helpers Boris Brezillon
2026-05-12 18:58 ` Chia-I Wu
2026-05-13 8:03 ` Boris Brezillon
2026-05-13 16:46 ` Chia-I Wu
2026-05-16 3:32 ` Claude review: " Claude Code Review Bot
2026-05-12 11:37 ` [PATCH v2 04/11] drm/panthor: Extend the IRQ logic to allow fast/hard IRQ handlers Boris Brezillon
2026-05-12 19:11 ` Chia-I Wu
2026-05-13 8:09 ` Boris Brezillon
2026-05-13 17:06 ` Chia-I Wu
2026-05-13 17:30 ` Boris Brezillon
2026-05-13 18:17 ` Chia-I Wu
2026-05-16 3:32 ` Claude review: " Claude Code Review Bot
2026-05-12 11:37 ` [PATCH v2 05/11] drm/panthor: Make panthor_fw_{update,toggle}_reqs() callable from IRQ context Boris Brezillon
2026-05-12 19:29 ` [PATCH v2 05/11] drm/panthor: Make panthor_fw_{update, toggle}_reqs() " Chia-I Wu
2026-05-16 3:32 ` Claude review: drm/panthor: Make panthor_fw_{update,toggle}_reqs() " Claude Code Review Bot
2026-05-12 11:37 ` [PATCH v2 06/11] drm/panthor: Prepare the scheduler logic for FW events in " Boris Brezillon
2026-05-12 21:04 ` Chia-I Wu
2026-05-13 8:29 ` Boris Brezillon
2026-05-13 17:47 ` Chia-I Wu
2026-05-16 3:32 ` Claude review: " Claude Code Review Bot
2026-05-12 11:37 ` [PATCH v2 07/11] drm/panthor: Automate CSG IRQ processing at group unbind time Boris Brezillon
2026-05-12 21:16 ` Chia-I Wu
2026-05-14 14:17 ` Steven Price
2026-05-16 3:32 ` Claude review: " Claude Code Review Bot
2026-05-12 11:37 ` [PATCH v2 08/11] drm/panthor: Automatically enable interrupts in panthor_fw_wait_acks() Boris Brezillon
2026-05-12 21:55 ` Chia-I Wu [this message]
2026-05-13 8:42 ` Boris Brezillon
2026-05-13 17:14 ` Chia-I Wu
2026-05-14 14:25 ` Steven Price
2026-05-16 3:32 ` Claude review: " Claude Code Review Bot
2026-05-12 11:37 ` [PATCH v2 09/11] drm/panthor: Process FW events in IRQ context Boris Brezillon
2026-05-12 22:05 ` Chia-I Wu
2026-05-12 22:09 ` Chia-I Wu
2026-05-13 8:44 ` Boris Brezillon
2026-05-14 15:23 ` Steven Price
2026-05-16 3:32 ` Claude review: " Claude Code Review Bot
2026-05-12 11:37 ` [PATCH v2 10/11] drm/panthor: Use the irqsave variant of spin_lock in panthor_gpu_irq_handler() Boris Brezillon
2026-05-14 15:26 ` Steven Price
2026-05-16 3:32 ` Claude review: " Claude Code Review Bot
2026-05-12 11:37 ` [PATCH v2 11/11] drm/panthor: Process GPU events in IRQ context Boris Brezillon
2026-05-12 11:50 ` Boris Brezillon
2026-05-12 22:40 ` Chia-I Wu
2026-05-13 8:54 ` Boris Brezillon
2026-05-13 18:07 ` Chia-I Wu
2026-05-16 3:32 ` Claude review: " Claude Code Review Bot
2026-05-16 3:32 ` Claude review: drm/panthor: Reduce dma_fence signalling latency Claude Code Review Bot
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