From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 338DB421235 for ; Mon, 7 Sep 2026 21:27:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788816443; cv=none; b=D4CzUIxjbuPiQSO/EEvOPbWWbt7zkdGZcHL4InLm2hGsUHClb0Tuqeq6CnUi6/pICkYiLZgOMFeR8zlDcqMJF+tlXGd1T+DFwZ2ClP5jk6Jao6znUR4oV4VqNDDQuxmYhLljsaZR7VXxd13RgZiXaqNISd3HXCctUnUSagwA598= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788816443; c=relaxed/simple; bh=nu4lZRkdykgD0lidZ6a++Q51KCf/JcVGvAwWam3AmWA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=pFxYBaMimU3DmCQA56aJp+/yHo4xtV6PZD2HzlINHPfDaChjmgCufQ784pX9DK4WRkiE/wi0Gj9NXMYua+nmAGCFsHVp+7ieh9fzb7Tc9Ku+ajgfYuRw5/57tAspUR3LDG33Eg9u0mnUsxJ1CzSaQgc+H4C2S5zEkK8kzb36iL0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=fatL9Iom; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="fatL9Iom" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1788816441; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=m+LuuZH7vy3arUdxfVYx5/xzHrxZVFqjwvjNWuwh10A=; b=fatL9Iom5QP1Di6S6H/CvccKB9atZTX6jn4KRwWXKmhVui8QmjISOmtXtvB/4z9DnrEbLP ZvM5xpvxaGQaCtZ+8ekCcBAspP+WTGsJa+h/Ohk9nvj+sd/I/+DaQP426BazX2MEOcWDRu npx7cdS2nnBaSHngLbHZpOkeS1pxosw= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-315-KShbRbIDMrKtni-SGAUjZA-1; Mon, 07 Sep 2026 17:27:18 -0400 X-MC-Unique: KShbRbIDMrKtni-SGAUjZA-1 X-Mimecast-MFC-AGG-ID: KShbRbIDMrKtni-SGAUjZA_1788816435 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 20AE3182FA4C; Mon, 7 Sep 2026 21:27:15 +0000 (UTC) Received: from [100.91.157.188] (headnet03.pony-001.prod.iad2.dc.redhat.com [10.2.32.114]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id E5A341800765; Mon, 7 Sep 2026 21:27:09 +0000 (UTC) Message-ID: Date: Mon, 7 Sep 2026 23:27:06 +0200 Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 12/14] drm/panic: Internalize panic locking in DRM core and helpers To: Thomas Zimmermann , javierm@redhat.com, airlied@gmail.com, simona@ffwll.ch, maarten.lankhorst@linux.intel.com, mripard@kernel.org, geert@linux-m68k.org, rdunlap@infradead.org Cc: dri-devel@lists.freedesktop.org, linux-doc@vger.kernel.org, amd-gfx@lists.freedesktop.org, rust-for-linux@vger.kernel.org, linux-hyperv@vger.kernel.org, intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, nouveau@lists.freedesktop.org, linux-renesas-soc@vger.kernel.org, virtualization@lists.linux.dev, sashiko-reviews@lists.linux.dev References: <20260902121930.597222-1-tzimmermann@suse.de> <20260902121930.597222-13-tzimmermann@suse.de> From: Jocelyn Falempe In-Reply-To: <20260902121930.597222-13-tzimmermann@suse.de> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 X-Mimecast-MFC-PROC-ID: urb-7UjVpyQbrvq4Xu5XYxzRVOfrnFe1K0xs0iexaS8_1788816435 X-Mimecast-Originator: redhat.com Content-Language: en-US, fr Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 9/2/26 14:13, Thomas Zimmermann wrote: > None of the DRM drivers handles panic locking. Declare the interfaces > in an internal header file. Move the trylock required during the panic > into the DRM core's sources. Thanks, it looks good to me. Reviewed-by: Jocelyn Falempe > > Signed-off-by: Thomas Zimmermann > --- > Documentation/gpu/drm-kms.rst | 3 ++ > MAINTAINERS | 3 +- > drivers/gpu/drm/drm_atomic_helper.c | 2 +- > drivers/gpu/drm/drm_drv.c | 2 +- > drivers/gpu/drm/drm_panic.c | 4 ++ > drivers/gpu/drm/drm_panic_internal.h | 55 +++++++++++++++++++++++ > include/drm/drm_panic.h | 65 ---------------------------- > 7 files changed, 66 insertions(+), 68 deletions(-) > create mode 100644 drivers/gpu/drm/drm_panic_internal.h > > diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst > index 0dd440a14946..8988fd64369b 100644 > --- a/Documentation/gpu/drm-kms.rst > +++ b/Documentation/gpu/drm-kms.rst > @@ -421,6 +421,9 @@ Plane Panic Functions Reference > .. kernel-doc:: include/drm/drm_panic.h > :internal: > > +.. kernel-doc:: drivers/gpu/drm/drm_panic_internal.h > + :internal: > + > .. kernel-doc:: drivers/gpu/drm/drm_panic.c > :export: > > diff --git a/MAINTAINERS b/MAINTAINERS > index c66c3fe93f3d..ccc5dc0a01ae 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -9111,7 +9111,8 @@ S: Supported > T: git https://gitlab.freedesktop.org/drm/misc/kernel.git > F: drivers/gpu/drm/drm_draw.c > F: drivers/gpu/drm/drm_draw_internal.h > -F: drivers/gpu/drm/drm_panic*.c > +F: drivers/gpu/drm/drm_panic.c > +F: drivers/gpu/drm/drm_panic_internal.h > F: drivers/gpu/drm/tests/drm_panic_test.c > F: include/drm/drm_panic.h > F: include/drm/drm_panic_helper.h > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c > index 285aac3554df..af3934df3313 100644 > --- a/drivers/gpu/drm/drm_atomic_helper.c > +++ b/drivers/gpu/drm/drm_atomic_helper.c > @@ -41,7 +41,6 @@ > #include > #include > #include > -#include > #include > #include > #include > @@ -49,6 +48,7 @@ > > #include "drm_crtc_helper_internal.h" > #include "drm_crtc_internal.h" > +#include "drm_panic_internal.h" > > /** > * DOC: overview > diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c > index 8c0879c336e5..64055514acbf 100644 > --- a/drivers/gpu/drm/drm_drv.c > +++ b/drivers/gpu/drm/drm_drv.c > @@ -51,13 +51,13 @@ > #include > #include > #include > -#include > #include > #include > #include > > #include "drm_crtc_internal.h" > #include "drm_internal.h" > +#include "drm_panic_internal.h" > > MODULE_AUTHOR("Gareth Hughes, Leif Delgass, José Fonseca, Jon Smirl"); > MODULE_DESCRIPTION("DRM shared core routines"); > diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c > index 7b9864857577..41ba0c4b050e 100644 > --- a/drivers/gpu/drm/drm_panic.c > +++ b/drivers/gpu/drm/drm_panic.c > @@ -35,6 +35,7 @@ > > #include "drm_crtc_internal.h" > #include "drm_draw_internal.h" > +#include "drm_panic_internal.h" > > MODULE_AUTHOR("Jocelyn Falempe"); > MODULE_DESCRIPTION("DRM panic handler"); > @@ -976,6 +977,9 @@ int drm_plane_helper_display_panic_screen(struct drm_plane *plane, const char *d > } > EXPORT_SYMBOL(drm_plane_helper_display_panic_screen); > > +#define drm_panic_trylock(dev, flags) \ > + raw_spin_trylock_irqsave(&(dev)->mode_config.panic_lock, flags) > + > static void drm_panic_display_panic_screen(struct drm_plane *plane, const char *description) > { > #if defined(CONFIG_DRM_PANIC_FOREGROUND_COLOR) > diff --git a/drivers/gpu/drm/drm_panic_internal.h b/drivers/gpu/drm/drm_panic_internal.h > new file mode 100644 > index 000000000000..c68d64c56e15 > --- /dev/null > +++ b/drivers/gpu/drm/drm_panic_internal.h > @@ -0,0 +1,55 @@ > +/* SPDX-License-Identifier: GPL-2.0 or MIT */ > + > +/* > + * Copyright (c) 2024 Intel > + * Copyright (c) 2024 Red Hat > + */ > + > +#ifndef __DRM_PANIC_INTERNAL_H__ > +#define __DRM_PANIC_INTERNAL_H__ > + > +#include > + > +struct drm_device; > + > +#ifdef CONFIG_DRM_PANIC > + > +/** > + * drm_panic_lock - protect panic printing relevant state > + * @dev: struct drm_device > + * @flags: unsigned long irq flags you need to pass to the unlock() counterpart > + * > + * This function must be called to protect software and hardware state that the > + * panic printing code must be able to rely on. The protected sections must be > + * as small as possible. It uses the irqsave/irqrestore variant, and can be > + * called from irq handler. Examples include: > + * > + * - Access to peek/poke or other similar registers, if that is the way the > + * driver prints the pixels into the scanout buffer at panic time. > + * > + * - Updates to pointers like &drm_plane.state, allowing the panic handler to > + * safely deference these. This is done in drm_atomic_helper_swap_state(). > + * > + * - An state that isn't invariant and that the driver must be able to access > + * during panic printing. > + */ > +#define drm_panic_lock(dev, flags) \ > + raw_spin_lock_irqsave(&(dev)->mode_config.panic_lock, flags) > + > +/** > + * drm_panic_unlock - end of the panic printing critical section > + * @dev: struct drm_device > + * @flags: irq flags that were returned when acquiring the lock > + * > + * Unlocks the raw spinlock acquired by either drm_panic_lock() or > + * drm_panic_trylock(). > + */ > +#define drm_panic_unlock(dev, flags) \ > + raw_spin_unlock_irqrestore(&(dev)->mode_config.panic_lock, flags) > + > +#else > +static inline void drm_panic_lock(struct drm_device *dev, unsigned long flags) {} > +static inline void drm_panic_unlock(struct drm_device *dev, unsigned long flags) {} > +#endif > + > +#endif /* __DRM_PANIC_INTERNAL_H__ */ > diff --git a/include/drm/drm_panic.h b/include/drm/drm_panic.h > index 430df536de14..99572b7eeab9 100644 > --- a/include/drm/drm_panic.h > +++ b/include/drm/drm_panic.h > @@ -8,11 +8,9 @@ > #ifndef __DRM_PANIC_H__ > #define __DRM_PANIC_H__ > > -#include > #include > #include > > -#include > #include > > struct page; > @@ -85,71 +83,8 @@ struct drm_scanout_buffer { > * set_pixel() > */ > void *private; > - > }; > > -#ifdef CONFIG_DRM_PANIC > - > -/** > - * drm_panic_trylock - try to enter the panic printing critical section > - * @dev: struct drm_device > - * @flags: unsigned long irq flags you need to pass to the unlock() counterpart > - * > - * The panic-printing code calls this function. The panic printing attempt must > - * be aborted if the trylock fails. > - * > - * Return: > - * %0 when failing to acquire the raw spinlock, nonzero on success. > - */ > -#define drm_panic_trylock(dev, flags) \ > - raw_spin_trylock_irqsave(&(dev)->mode_config.panic_lock, flags) > - > -/** > - * drm_panic_lock - protect panic printing relevant state > - * @dev: struct drm_device > - * @flags: unsigned long irq flags you need to pass to the unlock() counterpart > - * > - * This function must be called to protect software and hardware state that the > - * panic printing code must be able to rely on. The protected sections must be > - * as small as possible. It uses the irqsave/irqrestore variant, and can be > - * called from irq handler. Examples include: > - * > - * - Access to peek/poke or other similar registers, if that is the way the > - * driver prints the pixels into the scanout buffer at panic time. > - * > - * - Updates to pointers like &drm_plane.state, allowing the panic handler to > - * safely deference these. This is done in drm_atomic_helper_swap_state(). > - * > - * - An state that isn't invariant and that the driver must be able to access > - * during panic printing. > - */ > - > -#define drm_panic_lock(dev, flags) \ > - raw_spin_lock_irqsave(&(dev)->mode_config.panic_lock, flags) > - > -/** > - * drm_panic_unlock - end of the panic printing critical section > - * @dev: struct drm_device > - * @flags: irq flags that were returned when acquiring the lock > - * > - * Unlocks the raw spinlock acquired by either drm_panic_lock() or > - * drm_panic_trylock(). > - */ > -#define drm_panic_unlock(dev, flags) \ > - raw_spin_unlock_irqrestore(&(dev)->mode_config.panic_lock, flags) > - > -#else > - > -static inline bool drm_panic_trylock(struct drm_device *dev, unsigned long flags) > -{ > - return true; > -} > - > -static inline void drm_panic_lock(struct drm_device *dev, unsigned long flags) {} > -static inline void drm_panic_unlock(struct drm_device *dev, unsigned long flags) {} > - > -#endif > - > #if defined(CONFIG_DRM_PANIC_SCREEN_QR_CODE) > size_t drm_panic_qr_max_data_size(u8 version, size_t url_len); >