Re: [coreboot] Intel native graphics init: Questions about GTT setup: Decode error on Lenovo X60

[Paul Menzel]

Dear coreboot folks,

Am Montag, den 09.06.2014, 00:22 +0200 schrieb Paul Menzel:
> since Linux 3.12+ graphics stolen memory seems to be used, which causes
> a regression with coreboot and native graphics init at least on the
> Intel 945 based Lenovo X60 [1].
>
> This seems to be solved by properly setting register `PGETBL_CTL` [2],
> but the Linux kernel Intel graphics driver still reports a GTT (Graphics
> Translation Table) related error during start-up, but everything else
> seems to work.
>     [    1.235640] [drm] GPU crash dump saved to /sys/class/drm/card0/error
>     [    1.236583] [drm] GPU hangs can indicate a bug anywhere in the entire gfx stack, including userspace.
>     [    1.236583] [drm] Please file a _new_ bug report on bugs.freedesktop.org against DRI -> DRM/Intel
>     [    1.236583] [drm] drm/i915 developers can then reassign to the right component if it's not a kernel issue.
>     [    1.236583] [drm] The gpu crash dump is required to analyze gpu hangs, so please always attach it.
>     [    1.236583] i915: render error detected, EIR: 0x00000010
>     [    1.236583] i915: page table error
>     [    1.236583] i915:   PGTBL_ER: 0x00000013
>     [    1.236583] [drm:i915_report_and_clear_eir] *ERROR* EIR stuck: 0x00000010, masking
>     [    1.236583] i915: render error detected, EIR: 0x00000010
>     [    1.236583] i915: page table error
>     [    1.236583] i915:   PGTBL_ER: 0x00000013

With #5927 patch set 7 [2] the error is slightly different. (It needs to
be verified, if it is different during every run.)

[    1.235596] i915: render error detected, EIR: 0x00000010
        [    1.235596] i915: page table error
        [    1.235596] i915:   PGTBL_ER: 0x00000012
        [    1.235596] [drm:i915_report_and_clear_eir] *ERROR* EIR stuck: 0x00000010, masking
        [    1.235596] i915: render error detected, EIR: 0x00000010
        [    1.235596] i915: page table error
        [    1.235596] i915:   PGTBL_ER: 0x00000012
        [    1.310633] [drm:intel_modeset_init], 2 display pipes available.

The intel-gpu-tools [6] include the program `intel-error-decode`, which
give the following.

$ ./intel_error_decode /tmp/5927_7/error
        Time: 1402269737 s 277725 us
        Kernel: 3.14.4-gnuowen
        PCI ID: 0x27a2
        Detected GEN3 chipset
        EIR: 0x00000010
        IER: 0x00028053
        PGTBL_ER: 0x00000012
            Display A: Invalid GTT PTE
            Host Invalid PTE data
        […]

That register is not documented in the public Intel 945 datasheet [4].

Using the Intel 965 datasheet [5], page 206, there are the following
descriptions.

Bit 1: Valid PTE references illegal memory, such as PAM, SMM or TOM
Bit 4: Invalid GTT Entry during Display A Fetch

[…]

Thanks,

Paul
> [1] https://bugs.freedesktop.org/show_bug.cgi?id=79038
> [2] http://review.coreboot.org/5927
> [3] http://review.coreboot.org/#/c/5320/9/src/northbridge/intel/i945/gma.c
> [4] http://www.intel.com/content/dam/www/public/us/en/documents/datasheets/mobil...
> [5] https://01.org/linuxgraphics/sites/default/files/documentation/965_g35_vol_1...

[6] http://cgit.freedesktop.org/xorg/app/intel-gpu-tools/