EQUIPMENT Dell Inspiron 7537 (2013) Intel® Core™ i7-4510U CPU @ 2.00GHz × 4 Intel® Haswell Mobile
Kernel 4.8.4 (Fedora 24) Kernel boot parameters: acpi_osi=Linux acpi_rev_override nouveau.modeset=0 rd.driver.blacklist=nouveau rhgb quiet i915.enable_rc6=3 i915.enable_fbc=1 i915.semaphores=1 nmi_watchdog=0 pcie_aspm=force SYMPTOMS Battery is not detected on system boot with kernel 4.6 or newer (worked with 4.5). [root@dell9 ~]# dmesg | grep batt [ 1.248629] ACPI: Battery Slot [BAT0] (battery absent) It pops up when a brightness up/down key is pressed. REASON (probably) Older Linux kernels returned _REV=5, while newer return _REV=2. Dell ACPI (I tested all available BIOS versions from A09 to A13) will detect battery for Linux only if it gets _REV=5 from the kernel. More reading (with very detailed analysis): https://bugzilla.kernel.org/show_bug.cgi?id=105721#c19 WORKAROUND Use acpi_rev_override option which makes kernel return _REV=5 in old fashion. It works requires compiling own kernel (this option is NOT compiled into kernel by default) which is pain if you want to keep the system up-to-date. POSSIBLE SOLUTION (?) Abandon _REV=5 checking in DELL ACPI. I am not sure if my view on this issue is correct (i'm nowhere close to a specialist), but if so, I hope this bug is eventually fixed. Sorry if this bug has been reported already, I'm new to this list and I don't know how to browse the list archive. Dominik _______________________________________________ Linux-Desktops mailing list Linux-Desktops@dell.com https://lists.us.dell.com/mailman/listinfo/linux-desktops Please read the FAQ at http://lists.us.dell.com/faq
