diff options
Diffstat (limited to 'docs/future/old.html')
| -rw-r--r-- | docs/future/old.html | 277 |
1 files changed, 277 insertions, 0 deletions
diff --git a/docs/future/old.html b/docs/future/old.html new file mode 100644 index 0000000..7d72ec7 --- /dev/null +++ b/docs/future/old.html @@ -0,0 +1,277 @@ +<!DOCTYPE html> +<html lang="en"> +<head> + <meta charset="utf-8"> + <title>libreboot tutorials</title> + + <style type="text/css"> + body { + font-family: sans-serif; + font-size: 1em; + background: #fff; + color: #000; + } + + </style> + + <meta name="viewport" content="width=device-width, initial-scale=1.0"> + <meta name="author" content="glugman"> + <meta name="description" content="tutorials for libreboot, the reboot library."> + <meta name="robots" content="all"> +</head> + +<body> + + <header> + <h1 id="pagetop">Development notes (old/obsolete notes)</h1> + <aside>For current notes, see <a href="index.html">index.html</a>.</aside> + </header> + + <p> + These are old (obsolete) notes that mare kept because they might become useful again in the future. + </p> + +<hr/> + + <h2>Contents</h2> + <ul> + <li><a href="#x60_native_notes">X60 native graphics initialization (backlight controls)</a></li> + <li><a href="#t60_native_notes">T60 native graphics initialization (backlight controls)</a></li> + <li><a href="#5320_kernel312fix">i945: 3D fix (based on 5927) for kernel 3.12+ on 5320</a></li> + <li><a href="#x60_cb5927_testing">i945/x60: coreboot 5927 testing (3D fix for kernel 3.12+ on replay code)</a></li> + </ul> + +<hr/> + + <h1 id="x60_native_notes">X60 native graphics initialization (with backlight controls)</h1> + + <p> + <b> + This is now obsolete. A better way was found (included in libreboot): <a href="http://review.coreboot.org/#/c/6731/">http://review.coreboot.org/#/c/6731/</a> + </b> + </p> + + <p> + <b><i>Also check <a href="#5320_kernel312fix">#5320_kernel312fix</a> (to fix 3D on kernel 3.12/higher)</i></b> + </p> + <p> + <b>The fix below was done on 5320/6 (from review.coreboot.org) but should work just fine on later versions of 5320.</b> + </p> + <p> + Native gpu init + backlight controls! (Fn keys). Also confirmed on X60 Tablet (1024x768) and X60 Tablet (1400x1050) + </p> + <p> + <b>Add backlight controls:</b> in <i>src/mainboard/lenovo/x60/devicetree.cb</i>, change <b>gpu_backlight</b> to <b>0x879F879E</b> + </p> + <p> + That's all! <b>This has also been backported into libreboot 5th release (line 1233 in src/mainboard/lenovo/x60/i915io.c)</b>. GNUtoo (Denis Carikli) + told me about the register <b>BLC_PWM_CTL</b> and that you could set it to control backlight. I read that address using devmem2 while running the VBIOS:<br/> + <b># devmem2 0xe4361254 w</b> + </p> + <p> + The change is also included in libreboot 6. + </p> + <p> + When doing this, it gave back that value. The same trick was used to get backlight controls for T60 (see <a href="#t60_native_notes">#t60_native_notes</a>). + </p> + + <h2>Further notes</h2> + <p> + Reading <b>0xe4361254</b> (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 <b>lspci -vv</b> 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. + <b>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.</b>. + </p> + <p> + Intel-gpu-tools may prove useful for further debugging: <a href="http://cgit.freedesktop.org/xorg/app/intel-gpu-tools/">http://cgit.freedesktop.org/xorg/app/intel-gpu-tools/</a> + </p> + <p> + 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. + </p> + <p> + 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. + <b>Note: this may not be correct; he says his understanding is based on how the Lenote yeeloong works</b>. + </p> + <p> + 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 + </p> + <p> + phcoder (Vladimir Serbinenko) who is author of 5320 (review.coreboot.org) talks about 'duty cycle limit' and 'flickering frequency'. + </p> + + <p><a href="#pagetop">Back to top of page</a></p> + +<hr/> + + <h1 id="t60_native_notes">T60 native graphics initialization (with backlight controls)</h1> + + <p> + <b> + This is now obsolete. A better way was found (included in libreboot): <a href="http://review.coreboot.org/#/c/6731/">http://review.coreboot.org/#/c/6731/</a> + </b> + </p> + <p> + <b><i>Also check <a href="#5320_kernel312fix">#5320_kernel312fix</a> (to fix 3D on kernel 3.12/higher)</i></b> + </p> + <p> + <b>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</b> + </p> + <p> + <b>Add backlight controls:</b> in <i>src/mainboard/lenovo/t60/devicetree.cb</i>, change <b>gpu_backlight</b> to <b>0x58BF58BE</b> + </p> + <p> + Hold on! Check <a href="../index.html#get_edid_panelname">../index.html#get_edid_panelname</a> to know what LCD panel you have. This is important for the next step! + </p> + + <h2>Supported panels</h2> + <p> + <a href="../index.html#supported_t60_list">../index.html#supported_t60_list</a>. + </p> + + <p> + See <a href="#lcd_i945_incompatibility">#lcd_i945_incompatibility</a>. + </p> + + <p><a href="#pagetop">Back to top of page</a></p> + +<hr/> + + <h1 id="5320_kernel312fix">i945: 3D fix (based on 5927) for kernel 3.12+ on 5320</h1> + + <p> + <b> + This is now obsolete. Merged in coreboot: <a href="http://review.coreboot.org/#/c/5927/">http://review.coreboot.org/#/c/5927/</a> + </b> + </p> + + <p><b>This needs to be rewritten (or better organized, or deleted?)</b>. This is also now included in libreboot 6 (using the proper way, not the 7c0000 method which was a hack)</p> + + <p> + <b>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.</b> + </p> + + <p> + See <a href="#x60_cb5927_testing">#x60_cb5927_testing</a> for the original (and current) fix, for the replay code. Now we want + to implement that on top of <a href="http://review.coreboot.org/#/c/5320">http://review.coreboot.org/#/c/5320</a> + which is the current code for native graphics initialization on i945. + </p> + + <p> + src/northbridge/intel/i945/gma.c (using the 7c0000 hack) on 5320: <a href="dumps/5320_7c0000_gma.c">5320_7c0000_gma.c</a> (rename it to gma.c, + replacing the current one). + </p> + + <p> + 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. + </p> + + <p> + 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). + </p> + + <p> + Here is some debugging output using intel_gpu_tools v1.2-1 (from trisquel repositories) using tool "intel_gtt": + </p> + + <ul> + <li> + Trisquel 6. kernel 3.14.4: + <ul> + <li>with libreboot 5th release (using the 7c0000 gtt hack from 5927/3): <a href="http://paste.debian.net/104306">http://paste.debian.net/104306</a></li> + <li>with coreboot+vgarom: <a href="http://paste.debian.net/104309">http://paste.debian.net/104309</a></li> + </ul> + </li> + <li> + Trisquel 6. kernel 3.2.0-60 (from Trisquel repositories): + <ul> + <li>with coreboot (no vbios or native init): <a href="http://paste.debian.net/104341">http://paste.debian.net/104341</a></li> + </ul> + </li> + </ul> + + <p><a href="#pagetop">Back to top of page</a></p> + +<hr/> + + <h1 id="x60_cb5927_testing">i945/X60: Coreboot 5927 testing (3D fix for kernel 3.12+ on replay code)</h1> + + <p> + <b> + This is now obsolete. Merged in coreboot: <a href="http://review.coreboot.org/#/c/5927/">http://review.coreboot.org/#/c/5927/</a> + </b> + </p> + + <p><b>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.</b></p> + + <p> + 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). + </p> + + <p> + <b> + 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. + </b> + </p> + + <p> + Read the information on <a href="http://review.coreboot.org/#/c/5927/">http://review.coreboot.org/#/c/5927/</a>. + </p> + + <p> + For historical purposes, here is a collection of IRC logs that once existed on this page, related to the issue: + <a href="dumps/kernel312_irc">kernel312_irc</a>. + </p> + + <p> + PGETBL_CTL differs between VBIOS (-) and native graphics init (+).<br/> + + - PGETBL_CTL: 0x3ffc0001<br/> + + PGETBL_CTL: 0x3f800001 + </p> + + <p>GTT (graphics translation table) size is PGETBL_save, max 256 KiB. BSM (Base of Stolen Memory) is given by the bios.</p> + + <ul> + <li>5927/7: <a href="dumps/5927_7.tar.gz">5927_7.tar.gz</a> (GRUB graphics are correct now, and 3D still works)</li> + <li>5927/6: <a href="dumps/5927_6.tar.gz">5927_6.tar.gz</a> (GRUB graphics still corrupt, 3D/everything still works after GRUB)</li> + <li>5927/5: <a href="dumps/5927_5.tar.gz">5927_5.tar.gz</a> (GRUB graphics corrupt, 3D/everything still works after GRUB)</li> + <li>5927/3: <a href="dumps/5927_3.tar.gz">5927_3.tar.gz</a> (3D still works! kernel 3.14.4) - the '7c0000' hack</li> + <li>5927/2: <a href="dumps/5927_2.tar.gz">5927_2.tar.gz</a> (3D works! kernel 3.14.4) - the '7c0000' hack</li> + <li> + 5927/1 (didn't fix the 3D issue): + <ul> + <li><a href="dumps/5927_cbmemc">cbmem -c</a></li> + <li><a href="dumps/5927_crashdump">/sys/class/drm/card0/error</a></li> + <li><a href="dumps/5927_config">.config</a></li> + </ul> + </li> + </ul> + + <p><a href="#pagetop">Back to top of page</a></p> + +<hr/> + + <p> + Copyright © 2014 Francis Rowe <info@gluglug.org.uk><br/> + 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 <a href="../license.txt">../license.txt</a>. + </p> + + <p> + 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 <a href="../license.txt">../license.txt</a> for more information. + </p> + +</body> +</html> |