# No video input when I switch from X to console (Solved)

## Logicien

Hello,

I use the Vesafb framebuffer for characters terminals and ati-drivers (Fgrlx) with Xorg. I can switch from X to those terminals and come back to X normaly. What's appen at a time according to the OSD of my Philips 150 S VGA display, is I loose the video input when I switch form X to console. /dev/tty1 is the one I switch to the most. The screen go to sleep, I have no video output anymore, no shortcuts works. I precise I haven't loose the video input otherwhise.

The system work because I can ssh on it from an other machine. The only thing I can do from the host is to shutdown Gentoo using the power button ACPI even.

I do not know how to start to investigate this problem. Is it the kernel configuration and/or parameters, the Fglrx driver, the screen itself, or else?

My Gentoo installation have been switch from a laptop installation to a desktop. It changed after a while from UP to SMP kernel because the desktop processor is dual-core. Can it be the cause ? Is this way to loose of video input have been seen here?

I am gone try the Uvesafb for test. It seem's that the dual video drivers Vesafb/Fglrx conflict. Radeon KMS do not work.

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## Hu

In what way does Radeon KMS fail?

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## Logicien

KMS console black screen (Caicos Radeon HD 6450) (Unsolved)

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## Logicien

I do not loose video input with kernel framebuffer Uvesafb and Ati-drivers (Fglrx). The kernel parameter nocrtc like

```
cat /proc/cmdline

BOOT_IMAGE=/boot/vmlinuz noresume panic=10 quiet ro root=/dev/sda7 splash=silent,theme:Factice video=uvesafb:1024x768-32,mtrr:4,nocrtc,ywrap
```

do not change the BIOS frequency of the screen, 60 Hz so, all characters terminals work together with no flake. There delay X <-> console stay.

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## VoidMage

In case you've failed to read your own thread, notice, that you didn't post any real info (i.e. new system log), after you've dealt with missing firmware messages.

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## Logicien

I just want to tell the real reason why I was loosing the video signal. I putted the kernel parameter

```
video=vesafb:mtrr:4

or

video=uvesafb:mtrr:4
```

The MTRRs where modified by the kernel framebuffer in use, Vesafb or Uvesafb, to setup them for write-through. Fglrx set them for write-back by default. So, when switching from X to a framebuffer terminal, the MTRRs add to be changed. It was during that time that the screen OSD was displaying a short sleep mode message until the framebuffer drive the card. 

Possibly the MTRRs have not been restored (correctly) for the framebuffer driver at a moment. The result seem's to be that the graphic card was not drived anymore and no relay between Uvesafb/Vesafb and Fglrx was possible. The screen went to sleep mode permanently.

The system was working, the Internet connection was shared. Ignoring the cause of the problem, I haven't check via ssh the state of the MTRRs (cat /proc/mtrr).

When I changed the framebuffer kernel parameter for mtrr:3 (write-combining) or mtrr:0 (momtrr), the screen OSD stop to display this message. I haven't loose the video signal since then. As I have seen on the Internet, I finaly choose to disable completely the use of MTRRs by the framebuffer driver (mtrr:0 or nomtrr). A more scientific explanation can be done. I mark this problem as resolved.

About the non working Radeon KMS, ArchLinux, Gentoo and no live-cd have been able to work with. So, because it was working easily with all Radeon graphics cards I had before, I am just gone check with new kernels versions from live-cds if there is some progress with my dual GPU:

```
lspci

00:00.0 Host bridge: Advanced Micro Devices [AMD] Family 12h Processor Root Complex

00:01.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI Device 9644

00:01.1 Audio device: Advanced Micro Devices [AMD] nee ATI BeaverCreek HDMI Audio [Radeon HD 6500D and 6400G-6600G series]

00:02.0 PCI bridge: Advanced Micro Devices [AMD] Family 12h Processor Root Port

00:07.0 PCI bridge: Advanced Micro Devices [AMD] Family 12h Processor Root Port

00:10.0 USB controller: Advanced Micro Devices [AMD] Hudson USB XHCI Controller (rev 03)

00:10.1 USB controller: Advanced Micro Devices [AMD] Hudson USB XHCI Controller (rev 03)

00:11.0 SATA controller: Advanced Micro Devices [AMD] Hudson SATA Controller [AHCI mode] (rev 40)

00:12.0 USB controller: Advanced Micro Devices [AMD] Hudson USB OHCI Controller (rev 11)

00:12.2 USB controller: Advanced Micro Devices [AMD] Hudson USB EHCI Controller (rev 11)

00:13.0 USB controller: Advanced Micro Devices [AMD] Hudson USB OHCI Controller (rev 11)

00:13.2 USB controller: Advanced Micro Devices [AMD] Hudson USB EHCI Controller (rev 11)

00:14.0 SMBus: Advanced Micro Devices [AMD] Hudson SMBus Controller (rev 13)

00:14.2 Audio device: Advanced Micro Devices [AMD] Hudson Azalia Controller (rev 01)

00:14.3 ISA bridge: Advanced Micro Devices [AMD] Hudson LPC Bridge (rev 11)

00:14.4 PCI bridge: Advanced Micro Devices [AMD] Hudson PCI Bridge (rev 40)

00:14.5 USB controller: Advanced Micro Devices [AMD] Hudson USB OHCI Controller (rev 11)

00:18.0 Host bridge: Advanced Micro Devices [AMD] Family 12h/14h Processor Function 0 (rev 43)

00:18.1 Host bridge: Advanced Micro Devices [AMD] Family 12h/14h Processor Function 1

00:18.2 Host bridge: Advanced Micro Devices [AMD] Family 12h/14h Processor Function 2

00:18.3 Host bridge: Advanced Micro Devices [AMD] Family 12h/14h Processor Function 3

00:18.4 Host bridge: Advanced Micro Devices [AMD] Family 12h/14h Processor Function 4

00:18.5 Host bridge: Advanced Micro Devices [AMD] Family 12h/14h Processor Function 6

00:18.6 Host bridge: Advanced Micro Devices [AMD] Family 12h/14h Processor Function 5

00:18.7 Host bridge: Advanced Micro Devices [AMD] Family 12h/14h Processor Function 7

01:00.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI Caicos [Radeon HD 6450]

01:00.1 Audio device: Advanced Micro Devices [AMD] nee ATI Caicos HDMI Audio [Radeon HD 6400 Series]

02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 06)
```

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