[Bug 127168] vesafb sets the refresh rate too high for some LCDs

Fri Jul 20 13:54:01 UTC 2007

Public bug reported:

Binary package hint: linux-image-2.6-386

Hello!

I'm running Ubuntu Gutsy on a Dell Latitude D620 laptop with Intel
integrated video. See ddcprobe below.

X runs very well with the intel driver, although I'm using 915resolution
to get the native display resolution programmed into the video board
(1280x1024).

I've been trying for a week to get the same results in the console (or
at least more than VGA), with no success. I can't get intelfb to work (I
suspect vesafb is disabling it somehow, but I can't check until I
compile a new kernel, maybe later).

So I tried using the vesafb to get larger resolutions (1024x768), adding
this line (or similar) to the kernel parameters:

"video=vesafb:mtrr,ywrap,maxvf=60,1024x768-16 at 60 vga=0x317 hsync=60"

I've tried any combinations of the parameters, different resolutions,
bitdepths and refresh rates.  It seems to work, according to the
messages, but all I get is a blank, black screen. X comes up normally
when the boot is over. I can switch back and forth between X and the
consoles, but the consoles are always blank.

$ fbset

mode "1024x768-76"
    # D: 78.653 MHz, H: 59.949 kHz, V: 75.694 Hz
    geometry 1024 768 1024 768 16
    timings 12714 128 32 16 4 128 4
    rgba 5/11,6/5,5/0,0/0
endmode

According to fbset the refresh rate is always set at 76 Hz, and I'm sure
the screen allows only 60 (or 70, maybe, but I don't think so). This is
not a problem, since it's an LCD.

I know people have been asking for higher refresh rates at boot for a
long time (for CRTs), so maybe this is what caused the change (it worked
in Dapper or Feisty, not sure which). Is there any way to get a lower
refresh rate (preferably without recompiling the kernel)? And is there
any way to detect laptops with such problems and fix it automatically?

$ sudo ddcprobe 
vbe: VESA 3.0 detected.
oem: Intel(r) 82945GM Chipset Family Graphics Chip Accelerated VGA BIOS
vendor: Intel Corporation
product: Intel(r) 82945GM Chipset Family Graphics Controller Hardware Version 0.0
memory: 12288kb
mode: 1280x1024x256
mode: 1280x1024x64k
mode: 1280x1024x16m
mode: 1024x768x256
mode: 1024x768x64k
mode: 1024x768x16m
mode: 640x480x16m
mode: 800x600x64k
mode: 800x600x16m
mode: 640x480x256
mode: 800x600x256
mode: 640x480x64k
edid: 
edid: 1 3
id: 3157
eisa: SEC3157
serial: 00000000
manufacture: 0 2005
input: analog signal.
screensize: 30 19
gamma: 2.200000
dpms: RGB, no active off, no suspend, no standby
dtiming: 1280x800 at 59
monitorid: UD490141W1
monitorid: '7?Og���

$ lspci
00:00.0 Host bridge: Intel Corporation Mobile 945GM/PM/GMS/940GML and 945GT Express Memory Controller Hub (rev 03)
00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS/940GML Express Integrated Graphics Controller (rev 03)
00:02.1 Display controller: Intel Corporation Mobile 945GM/GMS/940GML Express Integrated Graphics Controller (rev 03)
00:1b.0 Audio device: Intel Corporation 82801G (ICH7 Family) High Definition Audio Controller (rev 01)
00:1c.0 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 1 (rev 01)
00:1c.1 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 2 (rev 01)
00:1c.2 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express Port 3 (rev 01)
00:1d.0 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #1 (rev 01)
00:1d.1 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #2 (rev 01)
00:1d.2 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #3 (rev 01)
00:1d.3 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI #4 (rev 01)
00:1d.7 USB Controller: Intel Corporation 82801G (ICH7 Family) USB2 EHCI Controller (rev 01)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev e1)
00:1f.0 ISA bridge: Intel Corporation 82801GBM (ICH7-M) LPC Interface Bridge (rev 01)
00:1f.2 IDE interface: Intel Corporation 82801GBM/GHM (ICH7 Family) Serial ATA Storage Controller IDE (rev 01)
00:1f.3 SMBus: Intel Corporation 82801G (ICH7 Family) SMBus Controller (rev 01)
03:01.0 CardBus bridge: O2 Micro, Inc. OZ601/6912/711E0 CardBus/SmartCardBus Controller (rev 40)
09:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5752 Gigabit Ethernet PCI Express (rev 02)
0c:00.0 Network controller: Intel Corporation PRO/Wireless 3945ABG Network Connection (rev 02)

** Affects: linux-meta (Ubuntu)
     Importance: Undecided
         Status: New

-- 
vesafb sets the refresh rate too high for some LCDs
https://bugs.launchpad.net/bugs/127168
You received this bug notification because you are a member of Kernel
Bugs, which is a bug contact for linux-meta in ubuntu.