drm/fb-helper: Initialize fb-helper's preferred BPP in prepare function

Initialize the fb-helper's preferred_bpp field early from within
drm_fb_helper_prepare(); instead of the later client hot-plugging
callback. This simplifies the generic fbdev setup function.

No real changes, but all drivers' fbdev code has to be adapted.

v3:
	* build with CONFIG_DRM_FBDEV_EMULATION unset (kernel test bot)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230125200415.14123-7-tzimmermann@suse.de

1 files changed, 2 insertions, 17 deletions

diff --git a/drivers/gpu/drm/drm_fbdev_generic.c b/drivers/gpu/drm/drm_fbdev_generic.c
index 63f66325a8a5..6ae014040df3 100644
--- a/drivers/gpu/drm/drm_fbdev_generic.c
+++ b/drivers/gpu/drm/drm_fbdev_generic.c
@@ -392,7 +392,7 @@ static int drm_fbdev_client_hotplug(struct drm_client_dev *client)
 	if (!drm_drv_uses_atomic_modeset(dev))
 		drm_helper_disable_unused_functions(dev);
 
-	ret = drm_fb_helper_initial_config(fb_helper, fb_helper->preferred_bpp);
+	ret = drm_fb_helper_initial_config(fb_helper);
 	if (ret)
 		goto err_cleanup;
 
@@ -454,7 +454,7 @@ void drm_fbdev_generic_setup(struct drm_device *dev,
 	fb_helper = kzalloc(sizeof(*fb_helper), GFP_KERNEL);
 	if (!fb_helper)
 		return;
-	drm_fb_helper_prepare(dev, fb_helper, &drm_fb_helper_generic_funcs);
+	drm_fb_helper_prepare(dev, fb_helper, preferred_bpp, &drm_fb_helper_generic_funcs);
 
 	ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_client_funcs);
 	if (ret) {
@@ -462,21 +462,6 @@ void drm_fbdev_generic_setup(struct drm_device *dev,
 		goto err_drm_client_init;
 	}
 
-	/*
-	 * Pick a preferred bpp of 32 if no value has been given. This
-	 * will select XRGB8888 for the framebuffer formats. All drivers
-	 * have to support XRGB8888 for backwards compatibility with legacy
-	 * userspace, so it's the safe choice here.
-	 *
-	 * TODO: Replace struct drm_mode_config.preferred_depth and this
-	 *       bpp value with a preferred format that is given as struct
-	 *       drm_format_info. Then derive all other values from the
-	 *       format.
-	 */
-	if (!preferred_bpp)
-		preferred_bpp = 32;
-	fb_helper->preferred_bpp = preferred_bpp;
-
 	ret = drm_fbdev_client_hotplug(&fb_helper->client);
 	if (ret)
 		drm_dbg_kms(dev, "client hotplug ret=%d\n", ret);