From 7eca665d684a734d55b0bb26c4f1831d399c5330 Mon Sep 17 00:00:00 2001 From: Francis Rowe Date: Mon, 28 Jul 2014 18:33:00 -0400 Subject: Libreboot release 6 beta 4. - Documentation: improved (more explanations, background info) in docs/howtos/x60_security.html (courtesy of Denis Carikli) - MacBook2,1 tested (confirmed) - macbook21: Added script 'macbook21_firstflash' for flashing libreboot while Apple EFI firmware is running. - Documentation: macbook21: added software-based flashing instructions for flashing libreboot while Apple EFI firmware is running. - Reduced size of libreboot_src.tar.gz: - Removed .git and .gitignore from grub directory (libreboot_src); not needed. Removing them reduces the size of the archive (by a lot). GRUB development should be upstream. - Removed .git and .gitignore from bucts directory (libreboot_src); not needed. Removing them reduces the size of the archive. bucts development should be upstream. - Removed .svn from flashrom directory (libreboot_src); not needed. Removing it reduces the size of the archive. flashrom development should be upstream. - Added ROM's with Qwerty (Italian) layout in GRUB (libreboot*itqwerty.rom) - Added resources/utilities/i945gpu/intel-regs.py for debugging issues related to LCD panel compatibility on X60 Tablet and T60. (courtesy of Michał Masłowski) --- (limited to 'docs/future/index.html') diff --git a/docs/future/index.html b/docs/future/index.html new file mode 100644 index 0000000..c525439 --- /dev/null +++ b/docs/future/index.html @@ -0,0 +1,741 @@ + + + + + libreboot tutorials + + + + + + + + + + + +
+

Development notes

+ +
+ +

+ Or go back to main document index. +

+ +
+ +

Contents

+ + +
+ +

TODO (bold means high priority)

+ + +

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+ +
+ +

standard test

+

+ These logs are usually obtained when testing changes related to graphics on i945 (X60 and T60). +

+ + +

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+ +
+ +

T60 cpu microcode

+ +

+ TODO: T60: find (for rare buggy CPU's that are unstable without microcode updates) if there is a workaround (patched kernel, special parameter, etc) So far, only 1 processor has been found to have issues. See microcode errata sheets http://download.intel.com/design/mobile/SPECUPDT/31407918.pdf and http://download.intel.com/design/mobile/SPECUPDT/30922214.pdf and then look at the debugging results collected in t7200q directory (q means quirk). +

+ +

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+ +
+ +

LCD panels on i945 - fix incompatible panels

+ +

+ Fix X60 Tablet issues (see incompatible panels listed at ../index.html#supported_x60t_list). +

+ +

+ Fix T60 issues (see incompatible panels listed at ../index.html#supported_t60_list). +

+ +

+ Run that tool (resources/utilities/i945gpu/intel-regs.py) as root on machines with the offending panels in: +

+ + +

+ This shows values in devicetree.cb and src/northbridge/intel/i945/gma.c, the idea is that you run it on factory bios or vbios + and that it will (might) show different values: then you try those in the native graphics (in libreboot). +

+ +

+ Other values/registers might also need to be added to the script for these tests. +

+ +

+ Original getregs.py script can be found at http://hg.mtjm.eu/scripts/file/tip/intel-regs.py + written by Michał Masłowski. +

+ +

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+ +
+ +

Blind X60 - kernel git bisect

+

+ Older kernels could init GPU on an X60 without a vbios or native graphics. + I have to do a git bisect to find out when that was broken. +

+ + + +

+ Note: "memory_corruption_check=0 i915.lvds_channel_mode=2" kernel parameters were once used + successfully for linux-libre 3.10 on a ThinkPad T60 (distribution: Parabola) to get graphics working. +

+ +

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+ +
+ +

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 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) +

+

+ Checkout http://review.coreboot.org/#/c/5320 on top of a coreboot git clone. +

+

+ 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 +

+

+ 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'. +

+ +

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+ +
+ +

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, but should work on the current version. +

+

+ Native gpu init + backlight controls! (Fn keys). Working on all panels except for 14" XGA (1024x768) and 15" XGA (1024x768)! +

+

+ Checkout http://review.coreboot.org/#/c/5320 + and then cherry-pick http://review.coreboot.org/#/c/5345 on top of a coreboot git clone. +

+

+ 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. +

+ +

+ Note to self: Run oprom trace for phcoder (T60 w/ 5320+5345 + oprom + grub) for phcoder. This (among other things) + might help to get all panels supported, without modification. +

+ +

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+ +
+ +

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": +

+ + + +

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+ +
+ +

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.

+ + + +

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+ +
+ +

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

+

+ Use 'drm.debug=0x06' kernel parameter when booting in grub! Make sure to use kernel 3.14.4 as before (or any recent kernel). +

+

+ Before each test run, boot a live USB and delete the old logs in /var/log (kernel log, xorg log, dmesg and so on). +

+

+ Use latest 5927/5320/5345 on X60/T60 (with GTT/3D/kernel3.12 fix) with native graphics initialization. + Load (from the ROM) the runningvga.bin for each LCD panel on each machine; do not execute it, only load it! + Rename the ROM appropriately, based on the machine name and the panel name. coreboot_nativegfx_5868_plusrunningvga_t60_14_LTD141ECMB.rom, + for instance. Keep a copy for later use. +

+ +

It is (theoretically) supposed to:

+ +

You are supposed to:

+ + +

+ With each boot, make notes about what you see and get logs using the standard test. + You will need the files from #intelvbttool_results for each machine. +

+ + Results (# means untested): + + +

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+ +
+ +

intelvbttool test results (VGA ROM's)

+

+ The VBIOS on i945 (intel gpu) platforms is self-modifying; that is, + it's contents change when you run it. intelvbttool takes a dump of + the currently running vbios, and parses it. +

+ +

+ The idea is that we can extract the VBT tables using this knowledge, on the X60, X60 Tablet and T60 (Intel GPU). +

+ +

+ Here is an example of how VBT was implemented on the ThinkPad X230: + http://review.coreboot.org/#/c/5396. +

+ +

+ Use this kernel: + http://samnoble.org/thinkpad/kernel/linux-image-3.14.4-gnuowen_2_i386.deb +

+ +

+ You'll need to build a T60 ROM with SeaBIOS and the VGA ROM (for Intel GPU). An X60 ROM is also needed (same configuration, using the VGA ROM for X60). +

+ +

+ T60 has DVI on it's dock, make sure that the dock is attached when getting this output. +

+ +

+ Get intelvbttool here: http://review.coreboot.org/#/c/5842 (util/intelvbttool). +

+ +

+ Now dump a copy of the running VGA BIOS: + $ sudo dd if=/dev/mem bs=64k of=runningvga.bin skip=12 count=1
+ Then do (and record the output):
+ $ ./intelvbttool runningvga.bin > intelvbttool_out +

+ +

+ Backup both files (runningvga.bin and intelvbttool_out), renaming them to match the machine and LCD panel used. + ../index.html#get_edid_panelname will show you how to get the name (model) of the LCD panel used. +

+ +

Test results (# means untested and all had docks, unless noted).

+ + + +

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+ +
+ +

Buzzing / static noise when not using idle=halt or processor.max_cstate=2 in GRUB

+ +

+ When idle, the X60 and T60 make a high pitched whining sound. With a recorder, find out where it originates from. + 'processor.max_cstate=2' or 'idle=halt' kernel parameters can be used in GRUB to remove it. + Alternatively (and for better battery life), another method is to use 'powertop' (see docs/index.html in libreboot release + archives). +

+ +

+ funfunctor in IRC says: "sounds like the gain is set to high, AGC of a ADC is not setup correctl probably". +

+

+ damo22 in IRC says: "damo22: it seems like the T60 (happens on X60 aswell) does not + support certain cpu C-states but is being forced to use them and this causes a noise. i believe it's because + it doesnt let the cpu go into low power state.". +

+

+ CareBear\ in IRC says: "it has to do with the CPU and chipset switching power states differently with coreboot than with the factory BIOS and as a result the power supply circuitry on the mainboard emits that noise. the whine is quite clearly directly related to the CPU switching between power states + " +

+ +

+ Another comment (mailing list):
+ If this noise doesn't occur with + the vendor firmware, has anybody checked if coreboot uses the same + power management timing settings? (e.g. C4-TIMING_CNT, see [1], there + might be more such settings not mentioned in the public datasheet)
+ [1] Intel I/O Controller Hub 7 (ICH7) Family Datasheet Document Number: 307013-003 +

+ +

+ +

+ +

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+ +
+ +

Battery 'event c' on X60 (and T60?)

+

+ Look into this later. This isn't necessarily a bug, just a part of the code which someone noticed that seems odd. +

+

+ funfuctor: fchmmr: what is 'eventc' exactly in the devicetree of your board? Is that meant to be programed sequentially somehow?
+ fchmmr: looks like something with EC
+ fchmmr: src/ec/lenovo/h8/chip.h: u8 eventc_enable;
+ fchmmr: src/ec/lenovo/h8/h8.c: ec_write(0x1c, conf->eventc_enable);
+ funfuctor: fchmmr: yes, better ask phcoder-screen why eventc is defined twice
+ funfuctor: and which value is correct
+ fchmmr: looks like 0x3c is incorrect
+ fchmmr: just a guess
+ fchmmr: in devicetree.cb it goes event2 then 3 4 5 6 7 c 8 9 then a b c d
+ fchmmr: but i don't know what 'event c' is
+ funfuctor: fchmmr: interesting, well in that case you could prob figure it out yourself..
+ funfuctor: fchmmr: the order should not matter. basically devicetree is syntax for fill in a C struct
+ funfuctor: fchmmr: look closely at build/mainboard/lenovo/t60/static.c
+ fchmmr: funfunctor: it was sven schnelle who wrote that (I used 'git blame')
+ fchmmr: I think "eventc" has something to do with battery
+ fchmmr: commit 95ebe66f7f5fef64d363cb48e5a441ad505353d1
+ fchmmr: Author: Sven Schnelle <svens@stackframe.org>
+ fchmmr: Date: Thu Apr 28 09:29:06 2011 +0000
+ fchmmr: that's the commit that added those lines.
+ fchmmr: funfunctor:
+ fchmmr: "" // C: OEM information
+ fchmmr: src/ec/lenovo/h8/acpi/battery.asl
+ funfuctor: fchmmr: i'll leave you with the issue of fixing the devicetree duplicate value
+ funfuctor: fchmmr: you need to read the datasheet to figure out what register 0x3C is
+ funfuctor: sorry *0x1C rather
+ funfuctor: grep eventc src/ec/lenovo/h8/h8.c
+ funfuctor: ec_write(0x1c, conf->eventc_enable);
+ Also look in src/ec/lenovo/h8/h8.c and src/ec/lenovo/h8/chip.h and src/mainboard/lenovo/x60/devicetree.cb
+ Do a 'git blame' and a 'git log path/to/file' etc. ask sven, even. +

+

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+ +
+ +

Unlisted Notes

+

+ funfunctor: shadow compiling means you run both compilers (context: GCC and Clang/LLVM) at the same time. If one compiler misses a problem the other compiler hopefully finds it
+ funfunctor: fchmmr: blow your mind (compiler security and reprodicible builds) - http://scienceblogs.com/goodmath/2007/04/15/strange-loops-dennis-ritchie-a/ +

+

+ Back to top of page. +

+ +

+ Copyright © 2014 Francis Rowe, All Rights Reserved.
+ See ../license.html for license conditions. +

+ + + -- cgit v0.9.1