Monitor doesn't display anything. EDID trouble ?

[Alex Deucher]

On Mon, Oct 24, 2011 at 3:01 PM, Xavier Bestel <xavier.bestel at free.fr> wrote:
> Hi,
>
> I know it may be off-topic, but the experience is there.
> I've just bought a used 30" monitor (HP ZR30w), and it doesn't display
> anything, even at BIOS time. The backlight is on, but I see nothing
> except a faint flickering at mode change times. Screen blanking works
> (the backlight switches off). I'm using a Radeon HD 5700 via DVI,
> debian/sid with kernel 3.1.0-rc7, Xorg 2:1.11.1.901-2 and radeon
> 1:6.14.2-2.
> After googling a bit, some people talk about a possible EDID problem
> (apparently it's possible to have the EDID somehow erased from the
> EEPROM ?). But Xorg.0.log does seem indicate that there's an EDID:
>
> [    21.829] (II) RADEON(0): Monitor name: HP ZR30w
> [    21.829] (II) RADEON(0): Serial No: CN4048041Z
> [    21.829] (II) RADEON(0): EDID (in hex):
> [    21.829] (II) RADEON(0):    00ffffffffffff0022f06e2801010101
> [    21.829] (II) RADEON(0):    3014010380402878ea8d85ad4f35b125
> [    21.829] (II) RADEON(0):    0e505400000001010101010101010101
> [    21.829] (II) RADEON(0):    010101010101e26800a0a0402e603020
> [    21.829] (II) RADEON(0):    360081902100001abc1b00a050201730
> [    21.829] (II) RADEON(0):    3020360081902100001a000000fc0048
> [    21.829] (II) RADEON(0):    50205a523330770a20202020000000ff
> [    21.829] (II) RADEON(0):    00434e343034383034315a0a20200066
> [    21.829] (II) RADEON(0): Printing probed modes for output DVI-0
> [    21.829] (II) RADEON(0): Modeline "2560x1600"x60.0  268.50  2560 2608 2640 2720  1600 1603 1609 1646 +hsync -vsync (98.7 kHz)
> [    21.829] (II) RADEON(0): Modeline "1280x800"x59.9   71.00  1280 1328 1360 1440  800 803 809 823 +hsync -vsync (49.3 kHz)
>
> ... and then:
>
> [    21.854] (II) RADEON(0): Output DVI-0 using initial mode 2560x1600
>
> Does anyone have an idea how I could pinpoint the problem ?

The EDID looks ok to me.  Do any other modes work?  Try 1280x800.  Try
the other DVI port.  If the neither port lights up the monitor
(especially if the bios produces no display), it's probably a bad
monitor.

Alex

>
> Thanks a lot,
>
>        Xav
>
>
>
> dmesg | grep drm
> [    0.998537] [drm] Initialized drm 1.1.0 20060810
> [    1.009248] [drm] radeon kernel modesetting enabled.
> [    1.009276] fb: conflicting fb hw usage radeondrmfb vs VESA VGA - removing generic driver
> [    1.009877] [drm] initializing kernel modesetting (JUNIPER 0x1002:0x68B8 0x1682:0x2994).
> [    1.009914] [drm] register mmio base: 0xFE7C0000
> [    1.009915] [drm] register mmio size: 131072
> [    1.010062] [drm] Detected VRAM RAM=1024M, BAR=256M
> [    1.010064] [drm] RAM width 128bits DDR
> [    1.010128] [drm] radeon: 1024M of VRAM memory ready
> [    1.010130] [drm] radeon: 512M of GTT memory ready.
> [    1.010139] [drm] Supports vblank timestamp caching Rev 1 (10.10.2010).
> [    1.010140] [drm] Driver supports precise vblank timestamp query.
> [    1.010189] [drm] radeon: irq initialized.
> [    1.010192] [drm] GART: num cpu pages 131072, num gpu pages 131072
> [    1.010720] [drm] Loading JUNIPER Microcode
> [    1.034007] [drm] ring test succeeded in 1 usecs
> [    1.034086] [drm] radeon: ib pool ready.
> [    1.034146] [drm] ib test succeeded in 0 usecs
> [    1.034517] [drm] Radeon Display Connectors
> [    1.034518] [drm] Connector 0:
> [    1.034519] [drm]   DisplayPort
> [    1.034520] [drm]   HPD4
> [    1.034521] [drm]   DDC: 0x6440 0x6440 0x6444 0x6444 0x6448 0x6448 0x644c 0x644c
> [    1.034523] [drm]   Encoders:
> [    1.034524] [drm]     DFP1: INTERNAL_UNIPHY2
> [    1.034525] [drm] Connector 1:
> [    1.034526] [drm]   DVI-I
> [    1.034527] [drm]   HPD1
> [    1.034528] [drm]   DDC: 0x6460 0x6460 0x6464 0x6464 0x6468 0x6468 0x646c 0x646c
> [    1.034529] [drm]   Encoders:
> [    1.034530] [drm]     DFP2: INTERNAL_UNIPHY1
> [    1.034531] [drm]     CRT2: INTERNAL_KLDSCP_DAC2
> [    1.034533] [drm] Connector 2:
> [    1.034533] [drm]   DVI-I
> [    1.034534] [drm]   HPD6
> [    1.034536] [drm]   DDC: 0x6450 0x6450 0x6454 0x6454 0x6458 0x6458 0x645c 0x645c
> [    1.034537] [drm]   Encoders:
> [    1.034538] [drm]     DFP3: INTERNAL_UNIPHY
> [    1.034539] [drm]     CRT1: INTERNAL_KLDSCP_DAC1
> [    1.512032] [drm] Radeon display connector DP-1: No monitor connected or invalid EDID
> [    1.563505] [drm] Radeon display connector DVI-I-1: Found valid EDID
> [    1.573120] [drm] Radeon display connector DVI-I-2: No monitor connected or invalid EDID
> [    1.573135] [drm] Internal thermal controller with fan control
> [    1.573174] [drm] radeon: power management initialized
> [    1.665202] [drm] fb mappable at 0xD0141000
> [    1.665203] [drm] vram apper at 0xD0000000
> [    1.665204] [drm] size 16384000
> [    1.665205] [drm] fb depth is 24
> [    1.665206] [drm]    pitch is 10240
> [    1.665288] fbcon: radeondrmfb (fb0) is primary device
> [    2.124952] fb0: radeondrmfb frame buffer device
> [    2.124954] drm: registered panic notifier
> [    2.124962] [drm] Initialized radeon 2.11.0 20080528 for 0000:01:00.0 on minor 0