From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yifeng Li Subject: [PATCH v2 6/7] fbdev: sm712fb: Kconfig: add information about docs. Date: Fri, 22 Mar 2019 13:17:58 +0800 Message-ID: <20190322051759.15007-7-tomli@tomli.me> References: <20190322051759.15007-1-tomli@tomli.me> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190322051759.15007-1-tomli@tomli.me> Sender: linux-kernel-owner@vger.kernel.org To: Sudip Mukherjee , Teddy Wang , linux-kernel@vger.kernel.org Cc: Bartlomiej Zolnierkiewicz , linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, Yifeng Li List-Id: dri-devel@lists.freedesktop.org This commits update the Kconfig description of sm712fb, and inform the user about the existence of documentation. Signed-off-by: Yifeng Li --- Documentation/fb/sm712fb.txt | 44 ++++++++++++++++++++---------------- drivers/video/fbdev/Kconfig | 4 ++++ 2 files changed, 29 insertions(+), 19 deletions(-) diff --git a/Documentation/fb/sm712fb.txt b/Documentation/fb/sm712fb.txt index 906b48aa40e4..c9a8fe059ac7 100644 --- a/Documentation/fb/sm712fb.txt +++ b/Documentation/fb/sm712fb.txt @@ -18,9 +18,10 @@ and it was also an inexpensive platform for non-x86 hobbyists to explore. How to use it? ============== -You should not compile-in vesafb, since SM7xx can be used in a VGA -compatible mode, resulting conflicts with this driver. In addition, -the VGA compatible mode was never tested by the maintainers. +SM7xx can be used in a VGA compatible mode and a native framebuffer mode, +this driver is a native driver. By default, it has no problem taking over +the VGA driver automatically, but you should not attempt to use both at +the same time. Currently, the driver supports 3 modes: 640x480, 800x600, 1024x768, at 16, 24 or 32-bit depth. Switching modes is done using the @@ -44,30 +45,35 @@ alpha channel, it's otherwise equal to 24-bit color. However, they could still be useful. For example, "fbterm" supports 32-bit mode but not 24-bit mode. -Notes about Modesetting +WARNING ======================== The modesetting code in sm712fb has major problems. -* Switching to 8-bit color mode will result in a black screen, so -they are removed from the list of supported graphic modes. But they -can still be switched to on-the-fly, don't do that then! +* If you are using a laptop, using a non-native resolution (for example, +using 640x480 on a 1024x768 screen) may garbled your LCD display, showing +a white screen. -* Only a refresh rate of 60 Hz is supported. +* The driver assumes a 1024x768 LCD by default, if you have a rare 800x600, +or 640x480 screen (e.g. Thinkpad 240X), it may garble your LCD by default. + +* The driver will crash/hang on systems with less than 2 MiB of VRAM, +(e.g. Thinkpad 240X), it cannot be fixed because the maintainers don't +have the hardware for testing. -* 1024x768 with 16-bit color is not really supported, because the -registers have been hacked by the original developer to adapt -the 1024x600 screen on Lemote YeeLoong 8089. +* Switching to 8-bit color mode will result in a black screen, so they are +removed from the list of supported graphic modes. But they can still be +switched to on-the-fly with fbset, don't do that then! -* If you are using a Lemote YeeLoong 8089, please remember that only -the 1024x768 modes are guaranteed to drive the LCD panel properly. -Other modes are meant to drive a CRT, and may drive the LCD incorrectly -and result in a white screen with random garbage. External VGA output is -unaffected. +* It is not possible to use different resolutions for LCD and VGA out. + +* Only a refresh rate of 60 Hz is supported. Due to the way registers are hardcoded, it's impossible to fix them -without a major code rewrite. If you've been hit by these problems badly -and really need to get them fixed, please contact the driver maintainers. +without a major code rewrite. + +If you've been hit by these problems badly and really need to get them +fixed, please contact the driver maintainers. 2D acceleration ============== @@ -97,7 +103,7 @@ Missing Features The following features are not implemented in this driver, - * 2D acceleration on SM720 and Big-Endian CPUs. + * 2D acceleration on Big-Endian CPUs. * More VGA modes. * dual-head support * hardware cursor support diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig index ae7712c9687a..4f3c0075352a 100644 --- a/drivers/video/fbdev/Kconfig +++ b/drivers/video/fbdev/Kconfig @@ -2302,6 +2302,10 @@ config FB_SM712 called sm712fb. If you want to compile it as a module, say M here and read . + Warning: this driver has many known problems and limitations, + please make sure you've checked the documentation, at + . + source "drivers/video/fbdev/omap/Kconfig" source "drivers/video/fbdev/omap2/Kconfig" source "drivers/video/fbdev/mmp/Kconfig" -- 2.20.1