path: root/drivers
diff options
authorChristian Trefzer <ctrefzer@gmx.de>2006-02-15 15:17:34 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-02-15 15:32:21 -0800
commit9f672004ab1a8094bec1785b39ac683ab9eebebc (patch)
tree75fc630226b2401ed7d2b5d15c2b149f2645cfd6 /drivers
parent[PATCH] fix zap_thread's ptrace related problems (diff)
[PATCH] neofb: avoid resetting display config on unblank (v2)
There were two mistakes in the register-read-on-(un)blank approach. - First, without proper register (un)locking the value read back will always be zero, and this is what I missed entirely until just now. Due to this, the logic could not be verified at all and I tried some bogus checks which are completely stupid. - Second, the LCD status bit will always be set to zero when the backlight has been turned off. Reading the value back during unblank will disable the LCD unconditionally, regardless of the state it is supposed to be in, since we set it to zero beforehand. So this is what we do now: - create a new variable in struct neofb_par, and use that to determine whether to read back registers (initialized to true) - before actually blanking the screen, read back the register to sense any possible change made through Fn key combo - use proper neoUnlock() / neoLock() to actually read something - every call to neofb_blank() determines if we read back next time: blanking disables readback, unblanking (FB_BLANK_UNBLANK) enables it This should give us a nice and clean state machine. Has been thoroughly tested on a Dell Latitude CPiA / NM220 Chip docked to a C/Dock2 with attached CRT in all possible combinations of LCD/CRT on/off. I changed the config via Fn key, let the console blank, unblanked by keypress - works flawlessly. Signed-off-by: Christian Trefzer <ctrefzer@gmx.de> Cc: "Antonino A. Daplas" <adaplas@pol.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers')
1 files changed, 12 insertions, 3 deletions
diff --git a/drivers/video/neofb.c b/drivers/video/neofb.c
index b85e2b180a44..a2e201dc40f7 100644
--- a/drivers/video/neofb.c
+++ b/drivers/video/neofb.c
@@ -843,6 +843,9 @@ static int neofb_set_par(struct fb_info *info)
par->SysIfaceCntl2 = 0xc0; /* VESA Bios sets this to 0x80! */
+ /* Initialize: by default, we want display config register to be read */
+ par->PanelDispCntlRegRead = 1;
/* Enable any user specified display devices. */
par->PanelDispCntlReg1 = 0x00;
if (par->internal_display)
@@ -1334,11 +1337,17 @@ static int neofb_blank(int blank_mode, struct fb_info *info)
struct neofb_par *par = info->par;
int seqflags, lcdflags, dpmsflags, reg;
- * Reload the value stored in the register, might have been changed via
- * FN keystroke
+ * Reload the value stored in the register, if sensible. It might have
+ * been changed via FN keystroke.
- par->PanelDispCntlReg1 = vga_rgfx(NULL, 0x20) & 0x03;
+ if (par->PanelDispCntlRegRead) {
+ neoUnlock();
+ par->PanelDispCntlReg1 = vga_rgfx(NULL, 0x20) & 0x03;
+ neoLock(&par->state);
+ }
+ par->PanelDispCntlRegRead = !blank_mode;
switch (blank_mode) {
case FB_BLANK_POWERDOWN: /* powerdown - both sync lines down */