Re: [PATCH v15 03/15] accel/rocket: wait for a running IRQ handler before resetting a core

From: "Heiko Stübner" <heiko@sntech.de>
To: tomeu@tomeuvizoso.net, robh@kernel.org, krzk+dt@kernel.org,
	conor+dt@kernel.org, joro@8bytes.org, will@kernel.org,
	robin.murphy@arm.com, ulfh@kernel.org, p.zabel@pengutronix.de,
	ogabbay@kernel.org, zhangqing@rock-chips.com,
	Jiaxing Hu <gahing@gahingwoo.com>
Cc: royalnet026@gmail.com, abel.vesa@oss.qualcomm.com,
	sebastian.reichel@collabora.com, sidong.yang@furiosa.ai,
	u.kleine-koenig@baylibre.com, chaoyi.chen@rock-chips.com,
	diederik@cknow-tech.com, alchark@flipper.net, leonard@lausen.nl,
	jeff.hugo@oss.qualcomm.com, rfoss@kernel.org,
	dri-devel@lists.freedesktop.org,
	linux-rockchip@lists.infradead.org, iommu@lists.linux.dev,
	linux-pm@vger.kernel.org, devicetree@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, Jiaxing Hu <gahing@gahingwoo.com>
Subject: Re: [PATCH v15 03/15] accel/rocket: wait for a running IRQ handler before resetting a core
Date: Tue, 03 Nov 2026 23:50:58 +0100	[thread overview]
Message-ID: <3311623.TQGk6oTFT5@diego> (raw)
In-Reply-To: <20261101082307.151957-4-gahing@gahingwoo.com>

Am Sonntag, 1. November 2026, 09:22:55 Mitteleuropäische Normalzeit schrieb Jiaxing Hu:
> drm_sched_stop() does not wait for a threaded handler that is already
> running. Call synchronize_irq() after it, outside job_lock, which the
> handler takes.
> 
> Before the sync, mask the block's interrupt and clear its raw status, so
> that an active core cannot signal a completion after it. Do that under
> job_lock, since rocket_job_hw_submit() arms the same mask under that lock,
> and only when pm_runtime_get_if_active() returns a positive count: the
> reset holds no runtime PM reference, and with the domain down a register
> access takes an async SError.
> 
> Igor Paunovic's induced-reset runs on RK3588, including a two-task job that
> puts hw_submit() on the IRQ thread, found no fault; as he put it, "this
> does not show the race is closed".
> 
> Link: https://lore.kernel.org/all/20260819073530.6087-1-royalnet026@gmail.com/
> Link: https://lore.kernel.org/all/CAEWPSH5mxTbUkNouxm6yecMZYvDowquhvYvhaXQ8HoMtHD5U1g@mail.gmail.com/
> Link: https://lore.kernel.org/all/20260912113717.6819-1-royalnet026@gmail.com/
> Link: https://lore.kernel.org/all/20260916132824.13527-1-royalnet026@gmail.com/
> Link: https://lore.kernel.org/all/20260919103422.148834-1-royalnet026@gmail.com/
> Suggested-by: Igor Paunovic <royalnet026@gmail.com>
> Signed-off-by: Jiaxing Hu <gahing@gahingwoo.com>
> Tested-by: Igor Paunovic <royalnet026@gmail.com> # RK3588, three cores, induced reset, JOB_TIMEOUT_MS=2
> ---
>  drivers/accel/rocket/rocket_job.c | 71 +++++++++++++++++++++++++++++--
>  1 file changed, 68 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/accel/rocket/rocket_job.c b/drivers/accel/rocket/rocket_job.c
> index 03e5f094f60b..5b2abf40b618 100644
> --- a/drivers/accel/rocket/rocket_job.c
> +++ b/drivers/accel/rocket/rocket_job.c
> @@ -401,9 +401,74 @@ rocket_reset(struct rocket_core *core, struct drm_sched_job *bad)
>  	drm_sched_stop(&core->sched, bad);
>  
>  	/*
> -	 * Remaining interrupts have been handled, but we might still have
> -	 * stuck jobs. Let's make sure the PM counters stay balanced by
> -	 * manually calling pm_runtime_put_noidle().

Also, why are you changing the original comment here?
The new wording below, does say essentially the same and you're changing
it again the next patch.

[...]

> +	/*
> +	 * No handler is running now, but we might still have stuck jobs. Let's
> +	 * make sure the PM counters stay balanced by manually calling
> +	 * pm_runtime_put_noidle().
>  	 */
>  	scoped_guard(mutex, &core->job_lock) {
>  		if (core->in_flight_job)
> 