From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A01BCFF8867 for ; Wed, 29 Apr 2026 13:32:50 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0852B10EFFD; Wed, 29 Apr 2026 13:32:50 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=arm.com header.i=@arm.com header.b="EDbyTLJC"; dkim-atps=neutral Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by gabe.freedesktop.org (Postfix) with ESMTP id 7C4A510EFFD for ; Wed, 29 Apr 2026 13:32:48 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5374E2574 for ; Wed, 29 Apr 2026 06:32:42 -0700 (PDT) Received: from [192.168.0.1] (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 899573F62B for ; Wed, 29 Apr 2026 06:32:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1777469567; bh=3dXqKoJqwgm37N7FLXaKeBBy5Wv7SRCuC+mUA6/f2+I=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=EDbyTLJC4CD5kKFmSRNqUOjlQx/ZDd5l9F+DX8xDEiRiKAC3uc9npQYmIvcmY4Yqt c3Kg0K6kAdx0Oxz5bJnTP3o9E8xMr1r4iNhajJqOgRtNMbnTRvIQ5GdwSrsKJoLMpD WBSCzoTQTC5rRXMlVfxMWsBcucrt/1ZOOcoC9zYQ= Date: Wed, 29 Apr 2026 14:32:39 +0100 From: Liviu Dudau To: Boris Brezillon Cc: Steven Price , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 04/10] drm/panthor: Extend the IRQ logic to allow fast/raw IRQ handlers Message-ID: References: <20260429-panthor-signal-from-irq-v1-0-4b92ae4142d2@collabora.com> <20260429-panthor-signal-from-irq-v1-4-4b92ae4142d2@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260429-panthor-signal-from-irq-v1-4-4b92ae4142d2@collabora.com> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Wed, Apr 29, 2026 at 11:38:31AM +0200, Boris Brezillon wrote: > All drivers except panthor signal their fences from their interrupt > handler to minimize latency. We could do the same from the interrupt > handler, but the latency is still quite high in that case, so let's > allow components to choose the context they want their IRQ handler > to run in. Starting here > > This takes the form of an extra fast_handler() returning an irqreturn_t > reflecting the need to wake-up a thread or not. > A new PANTHOR_IRQ_ADV_HANDLER() macro taking this extra fast_handler > argument is added, PANTHOR_IRQ_HANDLER() is implemented as a wrapper > around PANTHOR_IRQ_ADV_HANDLER() with a default fast_handler > returning IRQ_WAKE_THREAD. up to here: there is no code matching the description. Left over from earlier iteration? > The fast and slow handler are still assumed > to be mutually exclusive. In case a fast handler is provided, the > slow_handler is expected to be run when the event can't be processed > directly in the fast handler, or when the driver thinks it would be > beneficial to coalesce interrupts by polling in the thread rather than > re-enabling interrupts immediately. This part is not really describing any code, just the intent. Maybe worth moving it inside the code as a comment? Otherwise, the change looks fine to me. Reviewed-by: Liviu Dudau Best regards, Liviu > > Signed-off-by: Boris Brezillon > --- > drivers/gpu/drm/panthor/panthor_device.h | 5 ++--- > drivers/gpu/drm/panthor/panthor_fw.c | 1 + > drivers/gpu/drm/panthor/panthor_gpu.c | 1 + > drivers/gpu/drm/panthor/panthor_mmu.c | 1 + > drivers/gpu/drm/panthor/panthor_pwr.c | 1 + > 5 files changed, 6 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/panthor/panthor_device.h b/drivers/gpu/drm/panthor/panthor_device.h > index afa202546316..1c130b8394ab 100644 > --- a/drivers/gpu/drm/panthor/panthor_device.h > +++ b/drivers/gpu/drm/panthor/panthor_device.h > @@ -672,6 +672,7 @@ static inline void panthor_irq_disable_events(struct panthor_irq *pirq, u32 mask > static inline int > panthor_irq_request(struct panthor_device *ptdev, struct panthor_irq *pirq, > int irq, u32 mask, void __iomem *iomem, const char *name, > + irqreturn_t (*raw_handler)(int, void *data), > irqreturn_t (*threaded_handler)(int, void *data)) > { > const char *full_name; > @@ -687,9 +688,7 @@ panthor_irq_request(struct panthor_device *ptdev, struct panthor_irq *pirq, > if (!full_name) > return -ENOMEM; > > - return devm_request_threaded_irq(ptdev->base.dev, irq, > - panthor_irq_default_raw_handler, > - threaded_handler, > + return devm_request_threaded_irq(ptdev->base.dev, irq, raw_handler, threaded_handler, > IRQF_SHARED, full_name, pirq); > } > > diff --git a/drivers/gpu/drm/panthor/panthor_fw.c b/drivers/gpu/drm/panthor/panthor_fw.c > index eaf599b0a887..8239a6951569 100644 > --- a/drivers/gpu/drm/panthor/panthor_fw.c > +++ b/drivers/gpu/drm/panthor/panthor_fw.c > @@ -1483,6 +1483,7 @@ int panthor_fw_init(struct panthor_device *ptdev) > > ret = panthor_irq_request(ptdev, &fw->irq, irq, 0, > ptdev->iomem + JOB_INT_BASE, "job", > + panthor_irq_default_raw_handler, > panthor_job_irq_threaded_handler); > if (ret) { > drm_err(&ptdev->base, "failed to request job irq"); > diff --git a/drivers/gpu/drm/panthor/panthor_gpu.c b/drivers/gpu/drm/panthor/panthor_gpu.c > index ce208e384762..d0be758ea3e1 100644 > --- a/drivers/gpu/drm/panthor/panthor_gpu.c > +++ b/drivers/gpu/drm/panthor/panthor_gpu.c > @@ -177,6 +177,7 @@ int panthor_gpu_init(struct panthor_device *ptdev) > ret = panthor_irq_request(ptdev, &ptdev->gpu->irq, irq, > GPU_INTERRUPTS_MASK, > ptdev->iomem + GPU_INT_BASE, "gpu", > + panthor_irq_default_raw_handler, > panthor_gpu_irq_threaded_handler); > if (ret) > return ret; > diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c > index a0d0a9b2926f..2cb07933b629 100644 > --- a/drivers/gpu/drm/panthor/panthor_mmu.c > +++ b/drivers/gpu/drm/panthor/panthor_mmu.c > @@ -3260,6 +3260,7 @@ int panthor_mmu_init(struct panthor_device *ptdev) > ret = panthor_irq_request(ptdev, &mmu->irq, irq, > panthor_mmu_fault_mask(ptdev, ~0), > ptdev->iomem + MMU_INT_BASE, "mmu", > + panthor_irq_default_raw_handler, > panthor_mmu_irq_threaded_handler); > if (ret) > return ret; > diff --git a/drivers/gpu/drm/panthor/panthor_pwr.c b/drivers/gpu/drm/panthor/panthor_pwr.c > index 80cf78007896..1efb7f3482ba 100644 > --- a/drivers/gpu/drm/panthor/panthor_pwr.c > +++ b/drivers/gpu/drm/panthor/panthor_pwr.c > @@ -491,6 +491,7 @@ int panthor_pwr_init(struct panthor_device *ptdev) > err = panthor_irq_request( > ptdev, &pwr->irq, irq, PWR_INTERRUPTS_MASK, > pwr->iomem + PWR_INT_BASE, "pwr", > + panthor_irq_default_raw_handler, > panthor_pwr_irq_threaded_handler); > if (err) > return err; > > -- > 2.53.0 > -- ==================== | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- ¯\_(ツ)_/¯