From 96ca7ee67a36605a33de8d57eb8e8d3998bc6427 Mon Sep 17 00:00:00 2001 From: Michał Masłowski Date: Wed, 03 Sep 2014 14:30:21 -0400 Subject: Merge libreboot-6b6. Conflicts: buildrom-withgrub --- (limited to 'docs/future/index.html') diff --git a/docs/future/index.html b/docs/future/index.html index 3eee4f7..0bdabf4 100644 --- a/docs/future/index.html +++ b/docs/future/index.html @@ -24,7 +24,7 @@

Development notes

- +

@@ -41,10 +41,6 @@

  • Fast boot
  • LCD panels on i945 - fix incompatible panels
  • Blind X60 - kernel git bisect
    • -
  • X60 native graphics initialization (backlight controls)
    • -
  • T60 native graphics initialization (backlight controls)
    • -
  • i945: 3D fix (based on 5927) for kernel 3.12+ on 5320
    • -
  • i945/x60: coreboot 5927 testing (3D fix for kernel 3.12+ on replay code)
  • i945 X60/T60 VBT implementation (experimental: testing)
  • IntelVbtTool results
  • CPU c-states (X60/T60) buzzing sound on CPU idle
    • @@ -53,33 +49,6 @@
    -

    TODO (bold means high priority)

    - - -

    Back to top of page

    - -
    -

    standard test

    These logs are usually obtained when testing changes related to graphics on i945 (X60 and T60). @@ -289,199 +258,6 @@

    -

    X60 native graphics initialization (with backlight controls)

    -

    - Also check #5320_kernel312fix (to fix 3D on kernel 3.12/higher) -

    -

    - The fix below was done on 5320/6 (from review.coreboot.org) but should work just fine on later versions of 5320. -

    -

    - Native gpu init + backlight controls! (Fn keys). Also confirmed on X60 Tablet (1024x768) and X60 Tablet (1400x1050) -

    -

    - Add backlight controls: in src/mainboard/lenovo/x60/devicetree.cb, change gpu_backlight to 0x879F879E -

    -

    - That's all! This has also been backported into libreboot 5th release (line 1233 in src/mainboard/lenovo/x60/i915io.c). GNUtoo (Denis Carikli) - told me about the register BLC_PWM_CTL and that you could set it to control backlight. I read that address using devmem2 while running the VBIOS:
    - # devmem2 0xe4361254 w -

    -

    - The change is also included in libreboot 6. -

    -

    - When doing this, it gave back that value. The same trick was used to get backlight controls for T60 (see #t60_native_notes). -

    - -

    Further notes

    -

    - Reading 0xe4361254 (address) in Lenovo BIOS always yields FFFFFFFF, even when writing to it (and writing to it doesn't affect brightness controls). - 'mtjm' on IRC found that the buttons (Fn keys) control /sys/class/backlight/acpi_video0 which has no affect on 61254 (BLC_PWM_CTL). He says - intel_backlight has different values and uses the register. devmem2 works, needs checking lspci -vv for where the memory is mapped, - which is different than on coreboot; mtjm found that it was 0xec061254 on his machine (X60 Tablet), and the register value is different too. - This is relevant, because we still don't know how backlight controls are actually handled. We got it working by accident. We need to know more.. -

    -

    - Intel-gpu-tools may prove useful for further debugging: http://cgit.freedesktop.org/xorg/app/intel-gpu-tools/ -

    -

    - mtjm says 0xe4300000 is an MMIO region of the gpu (lspci -vv shows it), 0x61254 (BLC_PWM_CTL) is a documented register. Searching the kernel driver for backlight - shows that in intel_panel.c this register is used (there is an XXX comment about finding the right value, where recent kernels get it from. -

    -

    - What we want to do is calculate a good value, instead of setting it in devicetree.cb. mtjm says about backlight physics: - it has a light source , uses pulse width modulation (PWM) to turn it on/off, dimming is done by spending less time on. - Note: this may not be correct; he says his understanding is based on how the Lenote yeeloong works. -

    -

    - mtjm goes on to say, that the register specifies the frequency used for PWM in its depending on the GPU core frequency, so it - might be possible to calculate it without hardcoded laptop-specific values. Therefore, I am supposed to find out the 'display core frequency' - (mtjm says there might be a register for it; also, it might be in 5320 or the replay code) and the PWM modulation frequency. - https://en.wikipedia.org/wiki/Backlight#Flicker_due_to_backlight_dimming -

    -

    - phcoder (Vladimir Serbinenko) who is author of 5320 (review.coreboot.org) talks about 'duty cycle limit' and 'flickering frequency'. -

    - -

    Back to top of page

    - -
    - -

    T60 native graphics initialization (with backlight controls)

    -

    - Also check #5320_kernel312fix (to fix 3D on kernel 3.12/higher) -

    -

    - The fix below was done on an earlier version of 5345 changeset (review.coreboot.org), but should work on the current version. it is included in libreboot 6 -

    -

    - Add backlight controls: in src/mainboard/lenovo/t60/devicetree.cb, change gpu_backlight to 0x58BF58BE -

    -

    - Hold on! Check ../index.html#get_edid_panelname to know what LCD panel you have. This is important for the next step! -

    - -

    Supported panels

    -

    - ../index.html#supported_t60_list. -

    - -

    - See #lcd_i945_incompatibility. -

    - -

    Back to top of page

    - -
    - -

    i945: 3D fix (based on 5927) for kernel 3.12+ on 5320

    - -

    This needs to be rewritten (or better organized, or deleted?). This is also now included in libreboot 6 (using the proper way, not the 7c0000 method which was a hack)

    - -

    - This was done on 5320/6 so far. The fix below is for 5320/6 which is now obsolete. This needs to be re-done for the latest version - of 5320. The fix below is (in practise) only for reference, therefore. -

    - -

    - See #x60_cb5927_testing for the original (and current) fix, for the replay code. Now we want - to implement that on top of http://review.coreboot.org/#/c/5320 - which is the current code for native graphics initialization on i945. -

    - -

    - src/northbridge/intel/i945/gma.c (using the 7c0000 hack) on 5320: 5320_7c0000_gma.c (rename it to gma.c, - replacing the current one). -

    - -

    - The above is a hack (as is the original). A better (more correct) method is implemented in later versions of 5927, so - that should also be adapted for 5320. For now, you can use the above fix. -

    - -

    - The correct way to do it is to set gtt address to (end of stolen memory - gtt size), which is what later versions of 5927 do (successfully). -

    - -

    - Here is some debugging output using intel_gpu_tools v1.2-1 (from trisquel repositories) using tool "intel_gtt": -

    - - - -

    Back to top of page

    - -
    - -

    i945/X60: Coreboot 5927 testing (3D fix for kernel 3.12+ on replay code)

    - -

    The latest version as-is (5927/11) has not been tested by me yet. Always boot with 'drm.debug=0x06' kernel parameter when testing this.

    - -

    - This is the fix for 3D on kernel 3.12 and higher on i945 (ThinkPad X60 in this case). This is for the replay code. - Libreboot 5th release has a version of this backported already (based on 5927/3 using the '7c0000' hack). -

    - -

    - - The replay code is obsolete (see 5320 changeset on review.coreboot.org for better version - which supports more machines/screens, and then 5345 for T60). Information here for reference since that is where the fix was first applied. - -

    - -

    - Read the information on http://review.coreboot.org/#/c/5927/. -

    - -

    - For historical purposes, here is a collection of IRC logs that once existed on this page, related to the issue: - kernel312_irc. -

    - -

    - PGETBL_CTL differs between VBIOS (-) and native graphics init (+).
    - - - PGETBL_CTL: 0x3ffc0001
    - + PGETBL_CTL: 0x3f800001 -

    - -

    GTT (graphics translation table) size is PGETBL_save, max 256 KiB. BSM (Base of Stolen Memory) is given by the bios.

    - - - -

    Back to top of page

    - -
    -

    i945 gfx: X60/T60 VBT implementation (experimental: testing)

    intel_bios_dumper (use man) in intel-gpu-tools seems interesting. @@ -802,9 +578,18 @@ Back to top of page.

    +
    + +

    + Copyright © 2014 Francis Rowe <info@gluglug.org.uk>
    + This document is released under the Creative Commons Attribution-ShareAlike 4.0 International Public License and all future versions. + A copy of the license can be found at ../license.txt. +

    +

    - Copyright © 2014 Francis Rowe, All Rights Reserved.
    - See ../license.html for license conditions. + This document is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See ../license.txt for more information.

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