viafb: add X server compatibility mode

This patch adds a config option to be compatible with X servers like
OpenChrome. This is required as for example the X server does not
handle things like disabled IGAs/PLLs resulting in a potential
freeze on X startup. With this option disabled we can provide some
nice features like power management and not reinitializing the
hardware on every mode switch (taking long time, causing flickering).

Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>

2 files changed, 18 insertions, 0 deletions

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 6bafb51bb43..4923b5ec020 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -1607,6 +1607,17 @@ config FB_VIA_DIRECT_PROCFS
           correct output device configuration.
           Its use is strongly discouraged.
 
+config FB_VIA_X_COMPATIBILITY
+        bool "X server compatibility"
+        depends on FB_VIA
+        default n
+        help
+          This option reduces the functionality (power saving, ...) of the
+          framebuffer to avoid negative impact on the OpenChrome X server.
+          If you use any X server other than fbdev you should enable this
+          otherwise it should be safe to disable it and allow using all
+          features.
+
 endif
 
 config FB_NEOMAGIC
diff --git a/drivers/video/via/hw.c b/drivers/video/via/hw.c
index e5311474219..104f3e16010 100644
--- a/drivers/video/via/hw.c
+++ b/drivers/video/via/hw.c
@@ -2293,6 +2293,12 @@ int viafb_setmode(struct VideoModeTable *vmode_tbl, int video_bpp,
         clock.set_primary_clock_source(VIA_CLKSRC_X1, true);
         clock.set_secondary_clock_source(VIA_CLKSRC_X1, true);
 
+#ifdef CONFIG_FB_VIA_X_COMPATIBILITY
+        clock.set_primary_pll_state(VIA_STATE_ON);
+        clock.set_primary_clock_state(VIA_STATE_ON);
+        clock.set_secondary_pll_state(VIA_STATE_ON);
+        clock.set_secondary_clock_state(VIA_STATE_ON);
+#else
         if (viaparinfo->shared->iga1_devices) {
                 clock.set_primary_pll_state(VIA_STATE_ON);
                 clock.set_primary_clock_state(VIA_STATE_ON);
@@ -2308,6 +2314,7 @@ int viafb_setmode(struct VideoModeTable *vmode_tbl, int video_bpp,
                 clock.set_secondary_pll_state(VIA_STATE_OFF);
                 clock.set_secondary_clock_state(VIA_STATE_OFF);
         }
+#endif /*CONFIG_FB_VIA_X_COMPATIBILITY*/
 
         via_set_state(devices, VIA_STATE_ON);
         device_screen_on();