Any way to tell panel manufacturer for the rMBP 13"?

Discussion in 'MacBook Pro' started by Mac2k4, Oct 2, 2014.

  1. Mac2k4 macrumors newbie

    Joined:
    Sep 30, 2014
    #1
    Got my baby boy (13" rMBP today) and was wondering if there's any to tell who is the panel/display manufacturer? :confused: thanks
     
  2. NathanA macrumors 6502a

    Joined:
    Feb 9, 2008
    #2
    Forum search function says no.

    More seriously, the problem with the 13" is that it has no discrete GPU, and for some reason the Intel GPU drivers only ever return the first 128 bytes of the panel EDID. EDID started out being a uniform 128 bytes and only later versions of the spec added the ability for EDID size to be widened by using "enhanced EDID" (E-EDID) "extensions." So it kinda makes sense that certain things may only look at the first 128 bytes. In any case, the Retina panels only seem to contain information about the real model # of the panel (assigned by the actual manufacturer, and not Apple's BS 2-byte hex panel model numbers) in the E-EDID extensions past the 128th bit, and the nVidia drivers return the whole EDID but Intel drivers do not. So that's why owners of 15" rMBP with discrete graphics can get their panel information while other rMBP owners are forced to guess.

    There has got to be a way to extract the entire EDID from the panel using software...it's just nobody has found a way yet. I went as far as to try to use the DOS version of 'read-edid' (http://john.fremlin.de/programs/linux/read-edid/old.html) but the Mac EFI's BIOS emulation appears to not support the interrupt service that would normally return this information.

    -- Nathan
     
  3. vjobs macrumors regular

    Joined:
    Nov 23, 2013
    Location:
    Amsterdam, Netherlands
    #3
    Put this command in Terminal and press the return key.

    ioreg -lw0 | grep "EDID" | sed "/[^<]*</s///" | xxd -p -r | strings -6


    If it says LP it's a LG panel, if it says LSN it's a Samsung panel.
     
  4. Samuelsan2001 macrumors 604

    Joined:
    Oct 24, 2013
    #4
    Why worry about it if it is good?

    As long as it is a good panel what does it matter?? Unless there are any issues I'd just use and enjoy that retina lovliness.
     
  5. prism macrumors 6502a

    Joined:
    Dec 6, 2006
    #5
    You should read Nathan's answer before posting what you just did which does not work on the 13" rMBP given that it does not have a dGPU.
     
  6. poiihy macrumors 68020

    poiihy

    Joined:
    Aug 22, 2014
    #6
    What if it says LTN? Mine says LTN.
     
  7. NathanA macrumors 6502a

    Joined:
    Feb 9, 2008
    #7
    *sigh* Why don't people read responses before leading other people astray? This doesn't work on 13" rMBP. Period. All you will see with this command -- if anything -- is "Color LCD"

    What computer do you have? This thread is specifically about the 13" Retina MacBook Pro. If you are seeing anything other than "Color LCD" you probably don't have this computer, so this is the wrong discussion thread for you. However, I will mention that I believe I have heard others seeing "LTN" on MacBook Air, and I believe that it has been demonstrated that "LTN" is another Samsung panel model # designator (they have 2 or 3 different prefixes that they use, probably depending on the panel series or the technology it employs, such as TN or IPS or whatever).

    -- Nathan
     
  8. vjobs macrumors regular

    Joined:
    Nov 23, 2013
    Location:
    Amsterdam, Netherlands
    #8
    It works on my MBP 13" 2012 as well, so it doesn't depend on whether or not having a dGPU.

    Ps, MBP 13" has LG screen, same as my 15" Retina 2014. The 13" had great screen, returned a few 15" because of yellowing, now this one is nearly perfect.
     
  9. NathanA, Oct 5, 2014
    Last edited: Oct 5, 2014

    NathanA macrumors 6502a

    Joined:
    Feb 9, 2008
    #9
    I have to assume, unless you clarify otherwise, that you have a NON-retina 13" MBP from 2012. Your experience is an interesting data point; however, I feel compelled to point out that we are talking about rMBP in this thread, which I don't think is insignificant (especially since that's what the OP was asking about, after all). Still, the 2012 13" cMBP had Intel HD 4000 graphics, same as the late-2012 13" rMBP, so you might expect results to be similar.

    The difference may come in the EDID from the LCD panels themselves. Here's a question for you: how long is the EDID that is being returned to you? Run the same command, but without the "| xxd -p -r | strings -6" at the end, and then (ignoring the > at the tail end) count the length of the string that is returned to you. Is the hexadecimal number that you see there 256 digits (128 bytes) long, or is it 512 digits (256 bytes) long?

    If it is 256 digits long, then your non-Retina panel has a standard-length version 1.3 EDID. I see the same thing on my MacBook Air. For every retina panel that I've seen in the wild, however, there is a 512 digit long EDID, so a 128-byte-long EDID with an additional 128-byte-long E-EDID appended to the end.

    The actual panel details (including manufacturer-assigned model #) are only included in the E-EDID on these retina panels. If you look at the results from the grep (now removing the "| sed" bit and everything past it), on a Retina machine with discrete graphics, you will see that it picked out two results from the IOService tree matching the string "EDID": one called EDID and one called IODisplayEDID. The value of the EDID key is twice the length of the IODisplayEDID one (on a Retina machine with discrete graphics), which matches the former exactly except that it is truncated after the 256th digit. On a Retina without discrete graphics, only IODisplayEDID shows up, and it can be surmised that it is also truncated (but we don't have the whole EDID to compare it to on those machines, obviously). The EDID property exists under the NVDA,Display-A@0 branch (NVDA == nVidia, clearly) and IODisplayEDID under display0\AppleBacklightDisplay, which is quite a bit more generic sounding. The former is pretty evidently being generated by the nVidia driver, which of course isn't being used on non-discrete-graphics models.

    On my 2010 MacBook Air that has the nVidia 320M, I also see both EDID and IODisplayEDID. On this machine, both strings match exactly, and both are only 256 digits long (128-bytes in length).

    So my hypothesis is that on a machine with nVidia graphics, the nVidia graphics drivers are able to read and pass on the entirety of the EDID, but on other machines with Intel graphics, we are only being passed the first 128-bytes-worth of the EDID. On non-Retina machines, the panels that are being used only contain a 128-byte-long EDID, which can be successfully interrogated even on non-discrete-graphics models. But on Retina machines, the panels being used have 256-byte-long EDIDs and the contents of the panel's EDID cannot be retrieved past the 128th byte on models without nVidia graphics. Thus, at the present time, there is no way to retrieve complete panel details on *RETINA* MacBook Pros that do not have nVidia discrete graphics.

    -- Nathan
     

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