linux-kernel - [RFC PATCH v4 02/11] drm/fb-helper: Set FBINFO_MISC_FIRMWARE flag for DRIVER

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Date:   Fri, 29 Apr 2022 10:42:44 +0200
From:   Javier Martinez Canillas <javierm@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     dri-devel@...ts.freedesktop.org,
        Daniel Vetter <daniel.vetter@...ll.ch>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Javier Martinez Canillas <javierm@...hat.com>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...ux.ie>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>
Subject: [RFC PATCH v4 02/11] drm/fb-helper: Set FBINFO_MISC_FIRMWARE flag for DRIVER_FIRMWARE fb

The DRIVER_FIRMWARE flag denotes that a DRM driver uses a framebuffer
that was initialized and provided by the system firmware for scanout.

Indicate to the fbdev subsystem that the registered framebuffer is a
FBINFO_MISC_FIRMWARE, so that it can handle accordingly. For example,
wold hot-unplug the associated device if asked to remove conflicting
framebuffers.

Suggested-by: Thomas Zimmermann <tzimmermann@...e.de>
Signed-off-by: Javier Martinez Canillas <javierm@...hat.com>
---

(no changes since v1)

 drivers/gpu/drm/drm_fb_helper.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index d265a73313c9..76dd11888621 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1891,6 +1891,10 @@ __drm_fb_helper_initial_config_and_unlock(struct drm_fb_helper *fb_helper,
 		/* don't leak any physical addresses to userspace */
 		info->flags |= FBINFO_HIDE_SMEM_START;
 
+	/* Indicate that the framebuffer is provided by the firmware */
+	if (drm_core_check_feature(dev, DRIVER_FIRMWARE))
+		info->flags |= FBINFO_MISC_FIRMWARE;
+
 	/* Need to drop locks to avoid recursive deadlock in
 	 * register_framebuffer. This is ok because the only thing left to do is
 	 * register the fbdev emulation instance in kernel_fb_helper_list. */
-- 
2.35.1