linux-kernel - Re: DRM i915

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Message-ID: <CAKb7UvhFeZT4J81Gjh+mTAPsWWANPehxpAeYWApZuBL-4BjS3A@mail.gmail.com>
Date:   Sun, 8 Jan 2017 17:16:22 -0500
From:   Ilia Mirkin <imirkin@...m.mit.edu>
To:     Nathaniel Russell <naterussell83@...il.com>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: DRM i915

On Sun, Jan 8, 2017 at 5:01 PM, Nathaniel Russell
<naterussell83@...il.com> wrote:
> Any help figuring this out would be greatly appreciated.
> Linux version 4.8.15 (root@...dog) (gcc version 5.4.0 (GCC) ) #1 Sun Dec 18
> 22:48:37 CST 2016
>
>
>
>
> pci 0000:00:00.0: Intel G33 Chipset
> [    7.173121] pci 0000:00:00.0: detected gtt size: 524288K total, 262144K
> mappable
> [    7.173402] pci 0000:00:00.0: detected 8192K stolen memory
> [    7.173568] [drm] Memory usable by graphics device = 512M
> [    7.173651] [drm] Replacing VGA console driver
> [    7.174505] Console: switching to colour dummy device 80x25
> [    7.183053] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
> [    7.183068] [drm] Driver supports precise vblank timestamp query.
> [    7.183330] vgaarb: device changed decodes:
> PCI:0000:00:02.0,olddecodes=io+mem,decodes=io+mem:owns=io+mem
> [    7.187074] [drm] RC6 disabled, disabling runtime PM support
> [    7.187101] [drm] initialized overlay support
> [    7.187449] [drm] Initialized i915 1.6.0 20160711 for 0000:00:02.0 on
> minor 0
> [    7.253043] [drm:drm_edid_block_valid [drm]] *ERROR* EDID checksum is
> invalid, remainder is 62
> [    7.253061] Raw EDID:
> [    7.253068]      00 ff ff ff ff ff ff 00 10 ac 0b a0 53 4b 55 33
> [    7.253076]      2c 0e 01 03 68 22 1b 78 ee ca f6 a3 57 47 9e 23
> [    7.253084]      11 4f 54 a5 4b 00 71 4f 81 80 01 01 01 01 01 01
> [    7.253091]      01 01 01 01 01 01 30 2a 00 98 51 00 2a 40 30 70
> [    7.253098]      13 00 52 0e 11 00 00 1e 00 00 00 fd 00 38 4b 1f
> [    7.253106]      50 0e 00 0a 20 20 20 20 20 20 00 00 00 ff 00 44
> [    7.253113]      35 34 32 38 34 41 55 33 55 4b 53 0a 00 00 00 fc
> [    7.253121]      00 44 45 4c 4c 20 45 31 37 33 46 50 0a 20 00 98
> [    7.268019] usb 1-4.3: new high-speed USB device number 5 using ehci-pci
> [    7.287049] [drm:drm_edid_block_valid [drm]] *ERROR* EDID checksum is
> invalid, remainder is 62
> [    7.287067] Raw EDID:
> [    7.287074]      00 ff ff ff ff ff ff 00 10 ac 0b a0 53 4b 55 33
> [    7.287082]      2c 0e 01 03 68 22 1b 78 ee ca f6 a3 57 47 9e 23
> [    7.287090]      11 4f 54 a5 4b 00 71 4f 81 80 01 01 01 01 01 01
> [    7.287097]      01 01 01 01 01 01 30 2a 00 98 51 00 2a 40 30 70
> [    7.287105]      13 00 52 0e 11 00 00 1e 00 00 00 fd 00 38 4b 1f
> [    7.287112]      50 0e 00 0a 20 20 20 20 20 20 00 00 00 ff 00 44
> [    7.287120]      35 34 32 38 34 41 55 33 55 4b 53 0a 00 00 00 fc
> [    7.287127]      00 44 45 4c 4c 20 45 31 37 33 46 50 0a 20 00 98
> [    7.305052] firewire_ohci 0000:02:00.0: added OHCI v1.0 device as card 0,
> 8 IR + 8 IT contexts, quirks 0x0
> [    7.321041] [drm:drm_edid_block_valid [drm]] *ERROR* EDID checksum is
> invalid, remainder is 62
> [    7.321059] Raw EDID:
> [    7.321066]      00 ff ff ff ff ff ff 00 10 ac 0b a0 53 4b 55 33
> [    7.321074]      2c 0e 01 03 68 22 1b 78 ee ca f6 a3 57 47 9e 23
> [    7.321082]      11 4f 54 a5 4b 00 71 4f 81 80 01 01 01 01 01 01
> [    7.321089]      01 01 01 01 01 01 30 2a 00 98 51 00 2a 40 30 70
> [    7.321097]      13 00 52 0e 11 00 00 1e 00 00 00 fd 00 38 4b 1f
> [    7.321104]      50 0e 00 0a 20 20 20 20 20 20 00 00 00 ff 00 44
> [    7.321112]      35 34 32 38 34 41 55 33 55 4b 53 0a 00 00 00 fc
> [    7.321119]      00 44 45 4c 4c 20 45 31 37 33 46 50 0a 20 00 98
> [    7.335820] i801_smbus 0000:00:1f.3: SMBus using PCI interrupt
> [    7.349149] usb 1-4.3: New USB device found, idVendor=14cd,
> idProduct=125d
> [    7.349165] usb 1-4.3: New USB device strings: Mfr=1, Product=3,
> SerialNumber=2
> [    7.349178] usb 1-4.3: Product: Mass Storage Device
> [    7.349186] usb 1-4.3: Manufacturer: Generic
> [    7.349193] usb 1-4.3: SerialNumber: 125D20140310
> [    7.356045] [drm:drm_edid_block_valid [drm]] *ERROR* EDID checksum is
> invalid, remainder is 62
> [    7.356063] Raw EDID:
> [    7.356070]      00 ff ff ff ff ff ff 00 10 ac 0b a0 53 4b 55 33
> [    7.356078]      2c 0e 01 03 68 22 1b 78 ee ca f6 a3 57 47 9e 23
> [    7.356086]      11 4f 54 a5 4b 00 71 4f 81 80 01 01 01 01 01 01
> [    7.356093]      01 01 01 01 01 01 30 2a 00 98 51 00 2a 40 30 70
> [    7.356101]      13 00 52 0e 11 00 00 1e 00 00 00 fd 00 38 4b 1f
> [    7.356108]      50 0e 00 0a 20 20 20 20 20 20 00 00 00 ff 00 44
> [    7.356115]      35 34 32 38 34 41 55 33 55 4b 53 0a 00 00 00 fc
> [    7.356123]      00 44 45 4c 4c 20 45 31 37 33 46 50 0a 20 00 98
> [    7.356134] i915 0000:00:02.0: VGA-1: EDID block 0 invalid.

What's the question exactly? Your monitor is returning an EDID with an
invalid checksum, and the kernel is notifying you about this. The full
edid-decode output looks like:

$ ./edid-decode < tmp.edid
Extracted contents:
header:          00 ff ff ff ff ff ff 00
serial number:   10 ac 0b a0 53 4b 55 33 2c 0e
version:         01 03
basic params:    68 22 1b 78 ee
chroma info:     ca f6 a3 57 47 9e 23 11 4f 54
established:     a5 4b 00
standard:        71 4f 81 80 01 01 01 01 01 01 01 01 01 01 01 01
descriptor 1:    30 2a 00 98 51 00 2a 40 30 70 13 00 52 0e 11 00 00 1e
descriptor 2:    00 00 00 fd 00 38 4b 1f 50 0e 00 0a 20 20 20 20 20 20
descriptor 3:    00 00 00 ff 00 44 35 34 32 38 34 41 55 33 55 4b 53 0a
descriptor 4:    00 00 00 fc 00 44 45 4c 4c 20 45 31 37 33 46 50 0a 20
extensions:      00
checksum:        98

Manufacturer: DEL Model a00b Serial Number 861227859
EDID version: 1.3
Analog display, Input voltage level: 0.7/0.7 V
Sync: Separate
Maximum image size: 34 cm x 27 cm
Gamma: 2.20
DPMS levels: Standby Suspend Off
RGB color display
Default (sRGB) color space is primary color space
First detailed timing is preferred timing
Established timings supported:
  720x400@...z
  640x480@...z
  640x480@...z
  800x600@...z
  800x600@...z
  1024x768@...z
  1024x768@...z
  1280x1024@...z
Standard timings supported:
  1152x864@...z
  1280x1024@...z
Detailed mode: Clock 108.000 MHz, 338 mm x 270 mm
               1280 1328 1440 1688 hborder 0
               1024 1025 1028 1066 vborder 0
               +hsync +vsync
Monitor ranges (GTF): 56-75Hz V, 31-80kHz H, max dotclock 140MHz
Serial number: D54284AU3UKS
Monitor name: DELL
Checksum: 0x98 (should be 0x5a)
EDID block does NOT conform to EDID 1.3!
        Detailed block string not properly terminated
EDID block does not conform at all!
        Block has broken checksum
        Bad year of manufacture