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ATI 4650m and the 1600x900 LVDS via eDP

Black Screen WhiteLines Half resolution Dual Link

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#1
volram

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There is a big problem well known for the ATI mobility users: 1600x900 screen in LVDS is very difficult to attain. I think I have found the real motive for this. ATI uses, in some cases, the eDP output for connect with the internal lcd probably because of the high resolution of the panel. In my case the output is the following:


Connector Object Id [14] which is [LVDS]
encoder obj id [0x21] which is [INTERNAL_UNIPHY2 (osx txmit 0x12 [duallink 0x2] enc 0x4)] linkb: false
Connector Object Id [5] which is [VGA]
encoder obj id [0x15] which is [INTERNAL_KLDSCP_DAC1 (osx txmit 0x00 enc 0x10?)] linkb: false
Connector Object Id [12] which is [HDMI_TYPE_A]
encoder obj id [0x1e] which is [INTERNAL_UNIPHY (osx txmit 0x20 [duallink 0x0] enc 0x1)] linkb: true

But the transmitter 12/04 or 12/01 give me a black screen or half resolution (even with the dual link patch that can be made with chameleon, DSDT or via ATY_init plist).
The root of the problem, then, I think is the connector type. Reading the Linux driver info ( http://cgit.freedesk...ecac298b8d441d0) in the section Connector Object ID Definition has it:
-#define CONNECTOR_OBJECT_ID_eDP 0x14
As you can see, the connector that is identified as LVDS with the redsox bios decoder is really the eDP decoder. Kizwan has noted that some Imacs uses that port: http://www.insanelym...0#entry1662530.
The problem is that with the Shrike framebuffer Mountain Lion simply not load the GUI in my HP. How to solve that? I mean how to patch a framebuffer with this info i.e eDP output to enable LVDS connected via eDP. What are the connector type and control flags?

#2
azmod

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maybe it's the same problem found on any vaio with that card.. In my case with Lion, 4650m and 1920x1080 internal lcd I can only use safemode with 1400x1050 as max resolution and no QE/CI, in normal mode I've always had a gray screen with artifacts at login prompt..

#3
aunoor

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@volram, 14 in this output is not hex. 14=0xe.

#4
volram

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@volram, 14 in this output is not hex. 14=0xe.

@aunor, I Think that there is something in this direction. Take a look of a similar problem with the installation of Windows 7: http://support.micro....com/kb/978226. Note the reference to the Imac (4670m) in the description of the problem. However, some people with the connector object id [14] has been successful in getting the LVDS output. The problem should be in DSDT (sleep or lcd section). I noted that there is a interference between the lvds and hdmi output even though there is no conflict in the edited framebuff. When I plug the hdmi cable the lvds turn black (white line to backlight). More: when I plug a usb the lvds change the color (when it is not black). The problem is the conflict. Or the dual link pathc or the dsdt (sleep, usb, lcd). A big trouble.

#5
aunoor

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@volram, There is a another strange thing. LVDS with senseID = 7 mostly work without troubles. My Samsung R720 with 4650m have LVDS with sid=2 - black screen with any combinations.


VGA work

perfectly on any FB. But I don't try HDMI.

#6
volram

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@aunoor, I think the problem is not the senseID. I have senseID=7 and no luck. I have exactly the same information in the rom of my card that is in the rom of smartie77 available here: http://www.osx86.net...r_toshiba.html. The problem has to be located in dsdt.

#7
volram

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My early theory is confirmed. In some cases 4650 mobility (and perhaps a lot of others AMD mobility GPUs) uses the LVDS/eDP connector. The log of softMCCS confirmed that:

Skipping over LVDS/eDP on ATI Mobility Radeon HD 4650

We need help of some guru to solve the problem. I believe that I found the root of it.
You can find my softMCCS log here: https://mega.co.nz/#...wgUgNbG2iVxuuk.

#8
Extended

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Any news?







Also tagged with one or more of these keywords: Black Screen, WhiteLines, Half resolution, Dual Link


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