Topic Title: Seiki 4K monitor, Radeon 8670D, Linux framerate woes
Topic Summary: Only getting 14Hz refresh at 3840x2160
Created On: 06/06/2014 02:52 PM
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 06/06/2014 02:52 PM
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rfreebern
Peon

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Joined: 06/06/2014

I have Linux Mint running with a Seiki 4K monitor connected via HDMI to a Radeon 8670D. The monitor claims it supports 3840x2160 resolution at 30Hz over HDMI, and the 8670D can definitely provide that, but I haven't been able to get it to run above 14Hz. I've tried the open source fglrx driver as well as catalyst 14.4 and 14.6 with no luck.

Does anyone have any ideas of things I could try?

 06/06/2014 04:48 PM
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Eydee
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1. Have you tried addig the display mode through xrandr?

2. Have you tried creating a custom xorg.conf?



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CPU: AMD Phenom II X4 810 @ 3120MHz | RAM: Kingmax 2x2GB DDR2 800 @ 833MHz| MoBo: MSI K9A2 CF v1.0 (BIOS: 1.D)| GPU: Asus HD 6850 1024MB (DirectCu) @ 835/1135MHz | Display: L24FHD | PSU: PC Power & Cooling Silencer 750 Quad | OS: MS Windows 3.11 Pro x64

 06/06/2014 08:44 PM
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rfreebern
Peon

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I've tried adding many new display modes through xrandr at refresh rates between 14 and 30 Hz, but none of them worked. If there's another way to calculate the modelines than just using cvt I'm willing to try some more.

I was under the impression that xorg.conf was deprecated. If I can't set the modelines via xrandr, what sort of custom xorg.conf would potentially help?

 06/07/2014 06:32 AM
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Eydee
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Xorg.conf is "officially" deprecated. However, adding new display modes with xrandr are not preserved after a reboot, so it's kind of useless for anything but testing. Xorg.conf is permanent (until you change it.)



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CPU: AMD Phenom II X4 810 @ 3120MHz | RAM: Kingmax 2x2GB DDR2 800 @ 833MHz| MoBo: MSI K9A2 CF v1.0 (BIOS: 1.D)| GPU: Asus HD 6850 1024MB (DirectCu) @ 835/1135MHz | Display: L24FHD | PSU: PC Power & Cooling Silencer 750 Quad | OS: MS Windows 3.11 Pro x64

 06/07/2014 07:30 AM
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rfreebern
Peon

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Ah, good to know. So if I can figure out the magic modeline that makes the monitor work at its full refresh rate, I'll make sure to put it into an xorg.conf.

 06/09/2014 01:43 PM
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rfreebern
Peon

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For what it's worth, I reinstalled catalyst 14.6 and rebooted this morning, and now the monitor's running at 19Hz (and shows 16Hz and 13.8Hz as options). Still not as good as I hoped, but an improvement!

 07/12/2014 06:39 AM
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Larry Banana
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I have the exact same problem: Seiki 4K 39" monitor, AMD A8-5545M with  Radeon HD 8510G APU, Catalyst version 14.20-140522a-172181E

The first problem seems to be bad EDID/DDC data from the monitor causing Xorg to cough up:

EDID timing clock 297.00 exceeds claimed max 115MHz, fixing

which is a bit of a hack in handle_edid_quirks() in interpret_edid.c

So I tried to include setting "IgnoreEDID true" in the xorg.conf, but I found this ing the Xorg.0.log:

(WW) fglrx(0): Option "IgnoreEDID" is not used

Super!  This seems to be an Xorg thing to strip out functionality.

And then I created a custom Modeline for 3840x2160 @ 30 Hz:

        Modeline    "3840x2160_30" 297.0 3840 4016 4104 4400 2160 2168 2178 2250 -hsync +vsync

This modeline is based on the actual EDID data reported by the monitor:

(II) fglrx(0): Supported detailed timing:
(II) fglrx(0): clock: 297.0 MHz   Image Size:  854 x 481 mm
(II) fglrx(0): h_active: 3840  h_sync: 4016  h_sync_end 4104 h_blank_end 4400 h_border: 0
(II) fglrx(0): v_active: 2160  v_sync: 2168  v_sync_end 2178 v_blanking: 2250 v_border: 0


And here is where things just get fantastic!  In the Xorg.0.log, I find:

(EE) fglrx(0): Add Customize Mode failed: 7
(II) fglrx(0): Not using mode "3840x2160_30" (unknown reason)

Can it get any better than this?  Running strings on glrx_drv.so finds the offending strings in AMD's driver.

Add Customize Mode failed: %x

I have searched the web for information on this problem and all I have found were (a) people running into a 330 MHz pixel clock limitation (not a problem at 297 MHz) and (b) crickets.

Does anyone know if it is possible to correct the maximum pixel clock or why Xorg gets it wrong?  And is there a problem or upper limit on the driver pixel clock, say for this hardware?  And what is failure code "7"?  Even the driver doesn't seem to know.

 

 07/12/2014 08:12 AM
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Larry Banana
Peon

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After a bunch of experiments, "reason 7" appears to be "exceeds some arbitrary dot clock frequency" which may be hardware and/or driver dependent.  In my case, that frequency is 225 MHz.  How do I know?  Well, I tried both these Modelines:

        Modeline    "3840x2160_2282" 226 3840 4016 4104 4400 2160 2168 2178 2250 +hsync +vsync


        Modeline    "3840x2160_2272" 225 3840 4016 4104 4400 2160 2168 2178 2250 +hsync +vsync

The first one at 226 MHz fails "Add Customize Mode," while the second one passes and is used.  The Seiki, very graciously, accepts the 22.72 Hz frame rate and reports it as 22 Hz.

Great!  I'll just tweek the modeline timings to squeeze 24 Hz out of a 225 MHz dot clock and call it a day.

        Modeline    "3840x2160_24X"  225 3840 4016 4104 4281 2160 2168 2178 2190 +hsync +vsync

Oh, too bad, so sad.  X trips over a segmentation fault and dies.  From the backtrace, it seems that Xorg passed control to fglrx.so, who calls back into Xorg with bad parameters, upsetting the apple cart.  And this is why I love closed source so much: I can't do a thing about it.  I used to write Windows display drivers so it's not like I am completely clueless.  But modeset code was something to avoid if you could.  Something as simple as changing parameters on a PLL could lock you up if you didn't sequence the loads properly.

 07/12/2014 08:51 AM
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Larry Banana
Peon

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Eh, the driver was just feeling cranky.  Every modeline crashed after that.  A couple reboots, more crashes, and I finally commented out all the modelines.  And surprise, surprise, the driver has kept a list of the modelines it liked, somewhere, and is using the 24 Hz modeline.  Even thought the xorg.conf has had all the modelines and modes commented out.  Sometimes, undocumented code just works like magic.

 

 10/06/2014 11:10 AM
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rfreebern
Peon

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Over the weekend, we lost power and my system shut down for the first time since June. When I rebooted, X thought it was starting but the screen wasn't displaying anything, and the system was unresponsive to keyboard input.

Eventually, I uninstalled/reinstalled the latest Catalyst beta, and after rebooting, X came up fine at 3840x2160 @ 24Hz, which is the best refresh rate I've gotten yet. I have an aticonfig generated xorg.conf in place, but it essentially only contains generic info, and no special modelines or anything.

We'll see what happens next time I need to reboot!

 10/06/2014 03:25 PM
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d2_ricci
Peon

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You know, Sometimes the simple things are at fault. Do you have another HDMI cable to change to?  I've had some issues with certain cables (both cheap and expensive), Just a thought. 

And no I'm not saying you need to get a 4k approved HDMI cable, just a high speed hdmi cable is all.

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