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On Fri, Nov 13, 2015 at 03:54:02PM -0500, Walter Dnes wrote: |
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> I have 3 machines kicking around. One is a Dell Inspiron 530 from |
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> June 2008 that simply refuses to die. The others are more recent. |
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> On my desk (actually a re-purposed kitchen table) I only have room for 1 |
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> 24 inch monitor, 1 big Unicomp "IBM-like clickety-clack" USB keyboard |
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> http://www.pckeyboard.com/mm5/merchant.mvc?Screen=PROD&Product_code=UNI041A |
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> and 1 trackball. |
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> |
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> I got an IOGear 4-port USB KVM. It has a remote clicker to switch |
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> between the 4 ports; no icky escape/control sequences. Because it's |
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> hardware-controlled, there are no drivers required. It works great |
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> with one exception, which is a linux kernel problem, not a switch |
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> problem. The problem I've found occurs when booting a machine that is |
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> not currently selected by the KVM switch. I found the BIOS settings to |
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> eliminate the... |
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> |
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> Keyboard failure |
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> Select F1 to continue; F2 to enter SETUP |
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> |
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> ...message. The linux kernel problem is that it doesn't detect the |
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> display when that particular machine is not selected at bootup |
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> (duhhhh), and assumes 1024x768 console and graphics video. If the |
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> machine is selected by the switch at bootup, things work properly. |
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> |
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> But don't panic. Even if I boot into 1024x768 text mode, and default |
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> to 1024x768 graphics, running "xrandr -s 1920x1080" gets me 1920x1080 |
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> X Window display. The available modes for your display may be |
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> different. Just run "xrandr" for a list of available modes. |
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|
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Don't panic! |
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|
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There is a simple solution to this... Kernel developers have foreseen this |
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problem already! In your situation your graphics hardware is not getting |
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the EDID of your display, decause it is physically not connected to the |
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monitor when you boot up. See /Documentation/EDID for details. |
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|
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Set DRM_LOAD_EDID_FIRMWARE=y |
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|
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You can use x11-misc/read-edid to fetch edid from your monitor: |
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get-edid > your_edid.bin. Or you can use modedebug in xorg.conf and get |
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edid from Xorg.0.log |
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|
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Save the edid from your monitor to /lib/firmware/edid/ and include in your |
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kernel commandline "drm_kms_helper.edid_firmware=edid/your_edid.bin". You |
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can also set your video mode in comman line "video=DVI-I-1:1024x768@85". |
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The names for your connectors are found in "/sys/class/drm/*/status". |
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https://wiki.archlinux.org/index.php/Kernel_mode_setting |
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|
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These work with kernel mode setting. If you are using some proprietary |
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driver, see the documentation of that driver. At least with nvidia you |
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can set your custom edid in xorg.conf "Option CustomEDID DFP-0:/your_edid.bin" |
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and force monitors to be detected as connected at all times |
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"Option ConnectedMonitor DFP". |
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-M |
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