Blank screen with radeonfb in 2.6.22.1

lonehacker · 09-17-2007, 10:33 AM

I have a 'Radeon X300' aka RV370 5B60 and two 1920x1200 ACER LCDs on the DVI and VGA ports. Compiling in radeonfb and booting with 'video=radeonfb:1920x1200-32' causes a blank screen during kernel boot.

radeonfb debug output is enabled. From this it looks like the edid/i2c is not yielding correct results. I tried to work around this first with 'radeonfb=1920x1200-32,ignore_edid', then with 'radeonfb=1920x1200-32,ignore_edid,force_dfp,panel_yres=1200', but both had no effect.

In the dmesg output, at 'Guessing', it looks like the radeonfb driver is guessing wrong resolution.

Relevant dmesg output with 'radeonfb=1920x1200-32,ignore_edid,force_dfp,panel_yres=1200':

Code:

Linux version 2.6.22.1 (redacted@redacted) (gcc version 4.1.3 20070629 (prerelease) (Debian 4.1.2-13)) #1 SMP Sun Sep 9 03:11:05 EST 2007
Command line: root=/dev/sdb1 rootflags=data=writeback ro vga=795 video=radeonfb:1920x1200-32,ignore_edid,force_dfp,panel_yres=1200

Then later,

Code:

Boot video device is 0000:01:00.0
PCI: Setting latency timer of device 0000:00:0b.0 to 64
assign_interrupt_mode Found MSI capability
Allocate Port Service[0000:00:0b.0:pcie00]
Allocate Port Service[0000:00:0b.0:pcie03]
PCI: Setting latency timer of device 0000:00:0c.0 to 64
assign_interrupt_mode Found MSI capability
Allocate Port Service[0000:00:0c.0:pcie00]
Allocate Port Service[0000:00:0c.0:pcie03]
PCI: Setting latency timer of device 0000:00:0d.0 to 64
assign_interrupt_mode Found MSI capability
Allocate Port Service[0000:00:0d.0:pcie00]
Allocate Port Service[0000:00:0d.0:pcie03]
PCI: Setting latency timer of device 0000:00:0e.0 to 64
assign_interrupt_mode Found MSI capability
Allocate Port Service[0000:00:0e.0:pcie00]
Allocate Port Service[0000:00:0e.0:pcie03]
radeonfb_pci_register BEGIN
ACPI: PCI Interrupt Link [APC3] enabled at IRQ 18
ACPI: PCI Interrupt 0000:01:00.0[A] -> Link [APC3] -> GSI 18 (level, low) -> IRQ 18
radeonfb (0000:01:00.0): Found 131072k of DDR 64 bits wide videoram
radeonfb (0000:01:00.0): mapped 16384k videoram
radeonfb: Found Intel x86 BIOS ROM Image
radeonfb: Retrieved PLL infos from BIOS
radeonfb: Reference=27.00 MHz (RefDiv=12) Memory=325.00 Mhz, System=200.00 MHz
radeonfb: PLL min 20000 max 40000
1 chips in connector info
 - chip 1 has 2 connectors
  * connector 0 of type 2 (CRT) : 2300
  * connector 1 of type 3 (DVI-I) : 3201
Starting monitor auto detection...
i2c-adapter i2c-0: unable to read EDID block.
i2c-adapter i2c-0: unable to read EDID block.
i2c-adapter i2c-0: unable to read EDID block.
radeonfb: I2C (port 1) ... not found
radeonfb: I2C (port 2) ... found TMDS panel
i2c-adapter i2c-2: sendbytes: error - bailout.
i2c-adapter i2c-2: unable to read EDID block.
i2c-adapter i2c-2: sendbytes: error - bailout.
i2c-adapter i2c-2: unable to read EDID block.
radeonfb: I2C (port 3) ... found CRT display
radeonfb: I2C (port 4) ... not found
radeonfb: I2C (port 2) ... found TMDS panel
radeonfb: I2C (port 3) ... found CRT display
radeonfb: Monitor 1 type DFP found
radeonfb: Monitor 2 type CRT found
Guessing panel info...
radeonfb: Assuming panel size 1280x1025
hStart = 680, hEnd = 792, hTotal = 928
vStart = 401, vEnd = 404, vTotal = 417
h_total_disp = 0x4f0073    hsync_strt_wid = 0x8e02a2
v_total_disp = 0x18f01a0           vsync_strt_wid = 0x830190
pixclock = 9259
freq = 10800
freq = 10800, PLL min = 20000, PLL max = 40000
ref_div = 12, ref_clk = 2700, output_freq = 21600
ref_div = 12, ref_clk = 2700, output_freq = 21600
post div = 0x1
fb_div = 0x60
ppll_div_3 = 0x10060
Console: switching to colour frame buffer device 80x25
radeonfb (0000:01:00.0): ATI Radeon [`
radeonfb_pci_register END
input: Power Button (FF) as /class/input/input0
ACPI: Power Button (FF) [PWRF]
input: Power Button (CM) as /class/input/input1
ACPI: Power Button (CM) [PWRB]
ACPI: Fan [FAN] (on)
ACPI: Thermal Zone [THRM] (40 C)
Real Time Clock Driver v1.12ac
Linux agpgart interface v0.102 (c) Dave Jones
[drm] Initialized drm 1.1.0 20060810
[drm] Initialized radeon 1.27.0 20060524 on minor 0

GrapefruiTgirl · 09-17-2007, 12:11 PM

Hi there!

For one thing, though 32bit is technically correct, and is used in Windows, the same full-depth color under Linux is defined as 24 bit. Try changing the 32 to a 24.

Also, while I'm not familiar with the radeonfb device/driver or its capabilities, I think you will not get such a resolution during boot while using a framebuffer anyways. Not until X has started the graphical environment is running, will you get 1920x1200-24bpp.

As a test, either boot with no flags at all to make sure you get data on the screen under the normal circumstances, or boot with something safe like 640x480-16 or 1024x768-16 and if any of these works, then work your way up until you get a blank screen again, at which point you will have discovered the max resolution you can get from the framebuffer device.

Despite the capabilities of a video hardware device, the Linux framebuffer driver is not intended for crazy resolutions & graphics, so there's a limit to how much one can get out of it during boot.

I hope this helps you some, and if someone wants to correct me on any points I made about the framebuffer, please do, as this advice is 'to the best of my knowledge'.

best of success!