[PATCH 3/8] firmware: sysfb: Make CONFIG_SYSFB a user-selectable option

[Thomas Zimmermann <tzimmermann@suse.de>]

Add a descriptive string and help text to CONFIG_SYSFB, so that users
can modify it. Flip all implicit selects in the Kconfig options into
dependencies. This avoids cyclic dependencies in the config.

Enabling CONFIG_SYSFB makes the kernel provide a device for the firmware
framebuffer. As this can (slightly) affect system behavior, having a
user-facing option seems preferable. Some users might also want to set
every detail of their kernel config.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/firmware/Kconfig      | 18 ++++++++++++++++--
 drivers/gpu/drm/sysfb/Kconfig |  4 ++--
 drivers/hv/Kconfig            |  2 +-
 drivers/video/fbdev/Kconfig   |  5 +++--
 4 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index bbd2155d8483..52f8253a46b1 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -179,14 +179,28 @@ config MTK_ADSP_IPC
 	  Client might use shared memory to exchange information with ADSP.
 
 config SYSFB
-	bool
+	bool "Enable system framebuffer provided by boot loader"
 	select BOOT_VESA_SUPPORT
 	select SCREEN_INFO
+	help
+	  Use the system framebuffer provided by the boot loader. This will
+	  create a device representing the framebuffer. The output depends on
+	  EFI, VESA, VGA, or some other firmware-based interface.
+
+	  The firmware or boot loader sets the display resolution and color
+	  mode. See your boot loader's documentation on how to do this. On
+	  some systems the display can also be configured during boot with
+	  the kernel's video= or vga= parameters.
+
+	  Besides this option, you also have to enable a compatible graphics
+	  driver, such as efidrm or vesadrm.
+
+	  If unsure, say Y.
 
 config SYSFB_SIMPLEFB
 	bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
+	depends on SYSFB
 	depends on X86 || EFI
-	select SYSFB
 	help
 	  Firmwares often provide initial graphics framebuffers so the BIOS,
 	  bootloader or kernel can show basic video-output during boot for
diff --git a/drivers/gpu/drm/sysfb/Kconfig b/drivers/gpu/drm/sysfb/Kconfig
index 2559ead6cf1f..74be3c8e6657 100644
--- a/drivers/gpu/drm/sysfb/Kconfig
+++ b/drivers/gpu/drm/sysfb/Kconfig
@@ -26,12 +26,12 @@ config DRM_COREBOOTDRM
 config DRM_EFIDRM
 	tristate "EFI framebuffer driver"
 	depends on DRM && MMU && EFI && (!SYSFB_SIMPLEFB || COMPILE_TEST)
+	depends on SYSFB
 	select APERTURE_HELPERS
 	select DRM_CLIENT_SELECTION
 	select DRM_GEM_SHMEM_HELPER
 	select DRM_KMS_HELPER
 	select DRM_SYSFB_HELPER
-	select SYSFB
 	help
 	  DRM driver for EFI framebuffers.
 
@@ -76,12 +76,12 @@ config DRM_SIMPLEDRM
 config DRM_VESADRM
 	tristate "VESA framebuffer driver"
 	depends on DRM && MMU && X86 && (!SYSFB_SIMPLEFB || COMPILE_TEST)
+	depends on SYSFB
 	select APERTURE_HELPERS
 	select DRM_CLIENT_SELECTION
 	select DRM_GEM_SHMEM_HELPER
 	select DRM_KMS_HELPER
 	select DRM_SYSFB_HELPER
-	select SYSFB
 	help
 	  DRM driver for VESA framebuffers.
 
diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
index 2d0b3fcb0ff8..af0ac6516159 100644
--- a/drivers/hv/Kconfig
+++ b/drivers/hv/Kconfig
@@ -60,8 +60,8 @@ config HYPERV_BALLOON
 config HYPERV_VMBUS
 	tristate "Microsoft Hyper-V VMBus driver"
 	depends on HYPERV
+	depends on SYSFB if EFI && !HYPERV_VTL_MODE
 	default HYPERV
-	select SYSFB if EFI && !HYPERV_VTL_MODE
 	help
 	  Select this option to enable Hyper-V Vmbus driver.
 
diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig
index ac9ac4287c6a..6f55bec8c207 100644
--- a/drivers/video/fbdev/Kconfig
+++ b/drivers/video/fbdev/Kconfig
@@ -333,6 +333,7 @@ config FB_IMSTT
 config FB_VGA16
 	tristate "VGA 16-color graphics support"
 	depends on FB && X86
+	depends on SYSFB
 	select APERTURE_HELPERS
 	select FB_CFB_FILLRECT
 	select FB_CFB_COPYAREA
@@ -424,9 +425,9 @@ config FB_UVESA
 config FB_VESA
 	bool "VESA VGA graphics support"
 	depends on (FB = y) && X86
+	depends on SYSFB
 	select APERTURE_HELPERS
 	select FB_IOMEM_HELPERS
-	select SYSFB
 	help
 	  This is the frame buffer device driver for generic VESA 2.0
 	  compliant graphic cards. The older VESA 1.2 cards are not supported.
@@ -436,10 +437,10 @@ config FB_VESA
 config FB_EFI
 	bool "EFI-based Framebuffer Support"
 	depends on (FB = y) && EFI
+	depends on SYSFB
 	select APERTURE_HELPERS
 	select DRM_PANEL_ORIENTATION_QUIRKS
 	select FB_IOMEM_HELPERS
-	select SYSFB
 	help
 	  This is the EFI frame buffer device driver. If the firmware on
 	  your platform is EFI 1.10 or UEFI 2.0, select Y to add support for
-- 
2.53.0