linux-kernel - [PATCH v2] x86: sysfb: fool-proof CONFIG_X86

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Date:	Thu, 19 Dec 2013 17:18:30 +0100
From:	David Herrmann <dh.herrmann@...il.com>
To:	linux-kernel@...r.kernel.org
Cc:	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...nel.org>, <x86@...nel.org>,
	<linux-fbdev@...r.kernel.org>,
	David Herrmann <dh.herrmann@...il.com>,
	<stable@...r.kernel.org>
Subject: [PATCH v2] x86: sysfb: fool-proof CONFIG_X86_SYSFB

Turns out, people do not read help-texts of new config-options and enable
them nonetheless. So several reports came in with X86_SYSFB=y and
FB_SIMPLE=n, which in almost all situations prevents firmware-fbs from
being probed.

X86_SYSFB clearly states that it turns legacy vesa/efi framebuffers into a
format compatible to simplefb (and does nothing else..). So to avoid
further complaints about missing gfx-support during boot, simply depend on
FB_SIMPLE now.
As FB_SIMPLE is disabled by default and usually only enabled on selected
ARM architectures, x86 users should thus never see the X86_SYSFB
config-option. And if they do, everything is fine as simplefb will be
available.

Note that most of the sysfb code is enabled independently of X86_SYSFB.
The config option only selects a compatibility mode for simplefb. It was
introduced to ease the transition to SimpleDRM and disabling fbdev. As
this is still ongoing, there's no need for non-developers to care for
X86_SYSFB so we can safely hide it behind FB_SIMPLE.

Cc: <stable@...r.kernel.org> # 3.11+
Signed-off-by: David Herrmann <dh.herrmann@...il.com>
---
v2:
 - keep the "If unsure, say Y"
 - (FB_SIMPLE = y) => FB_SIMPLE
 - adjust commit-msg

 arch/x86/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index e903c71..c9d2952 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2298,6 +2298,7 @@ source "drivers/rapidio/Kconfig"

 config X86_SYSFB
 	bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
+	depends on FB_SIMPLE
 	help
 	  Firmwares often provide initial graphics framebuffers so the BIOS,
 	  bootloader or kernel can show basic video-output during boot for
-- 
1.8.5.1

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