<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_REOPENED " title="REOPENED - [BYT LPSS backlight] Acer Aspire Switch 10 backlight control" href="https://bugs.freedesktop.org/show_bug.cgi?id=90075#c14">Comment # 14</a> on <a class="bz_bug_link bz_status_REOPENED " title="REOPENED - [BYT LPSS backlight] Acer Aspire Switch 10 backlight control" href="https://bugs.freedesktop.org/show_bug.cgi?id=90075">bug 90075</a> from <a class="email" href="mailto:darlor@seznam.cz" title="darlor@seznam.cz">darlor@seznam.cz</a> <pre>Created <a href="attachment.cgi?id=133201" name="attach_133201" title="dsdt.dsl from bios version 1.18">attachment 133201</a> <a href="attachment.cgi?id=133201&action=edit" title="dsdt.dsl from bios version 1.18">[details]</a> dsdt.dsl from bios version 1.18 Hello again, just to let you know, even Hans de Goede`s linux-sunxi [1] with a lot of not-yet-upstreamed patches for baytrail/cherrytrail does not work. Strange thing is that this kernel supports lpss-pwm for certain devices (accoring Hans` Hacking Blog), but on Acer Switch 10 dmesg there is: [drm] Using crystal_cove_wpm pwm-device for backlight control. I inserted a lot of debuging printk messages into sunxi, and there is nothing indicating that lpss should be used for Switch 10. (but maybe I did something wrong - modules pwm-lpss and pwm-lpss-platform forced to load from initrd.img, and i915 module loaded later (via modprobe manualy)) In sunxi I find some commits very interesting: ACPI / LPSS: Only call pwm_add_table() for Bay Trail PWM if PMIC HRV is 2 [2] mfd: intel_soc_pmic: Differentiate between Bay and Cherry Trail CRC variants [3] mfd: intel_soc_pmic: Export separate mfd-cell configs for BYT and CHT [4] and very very interesting ACPI / bus: Introduce a list of ids for "always present" devices "Several Bay / Cherry Trail devices (all of which ship with Windows 10) hide the LPSS PWM controller in ACPI..." Maybe Hans De Goede could shed some light on this issue. [1] <a href="https://github.com/jwrdegoede/linux-sunxi">https://github.com/jwrdegoede/linux-sunxi</a> [2] <a href="https://github.com/jwrdegoede/linux-sunxi/commit/44eb7ab01b1a3bd3d70f623df013c314e8032316">https://github.com/jwrdegoede/linux-sunxi/commit/44eb7ab01b1a3bd3d70f623df013c314e8032316</a> [3] <a href="https://github.com/jwrdegoede/linux-sunxi/commit/118c804aa8ba9be46667cbafa1755c058e47ed77">https://github.com/jwrdegoede/linux-sunxi/commit/118c804aa8ba9be46667cbafa1755c058e47ed77</a> [4] <a href="https://github.com/jwrdegoede/linux-sunxi/commit/cb63e6df172879b5476ae704c87bd06ba391a1f9">https://github.com/jwrdegoede/linux-sunxi/commit/cb63e6df172879b5476ae704c87bd06ba391a1f9</a> [5] <a href="https://github.com/jwrdegoede/linux-sunxi/commit/b7ecf663c75eed1e764f57281f9508c49c18516e">https://github.com/jwrdegoede/linux-sunxi/commit/b7ecf663c75eed1e764f57281f9508c49c18516e</a> I`m including dsdt.dsl_ver1.18 from bios versions 1.18 (I was not able to upgrade to last 1.20 version via W8). Maybe using custom dsdt could work around this issue, until (if ever) is this issue solved.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are on the CC list for the bug.</li> <li>You are the QA Contact for the bug.</li> <li>You are the assignee for the bug.</li> </ul> </body> </html>