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

From: Javier Martinez Canillas
Date: Fri Apr 29 2022 - 04:43:26 EST


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@xxxxxxx>
Signed-off-by: Javier Martinez Canillas <javierm@xxxxxxxxxx>
---

(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