From 96667b897c71a159b201369d544cde0e625f855e Mon Sep 17 00:00:00 2001 From: Charles Samborski Date: Tue, 17 Jul 2018 09:50:15 +0200 Subject: [PATCH] Document `acpi_rev_override` kernel parameter This commit adds document the `acpi_rev_override` kernel parameter. Setting this parameter is necessary on some computers to avoid black screen at boot time. See Bumblebee-Project/bbswitch#148 --- README.md | 28 +++++++++++++++++++--------- 1 file changed, 19 insertions(+), 9 deletions(-) diff --git a/README.md b/README.md index 11ad3d7..b7d0c2b 100644 --- a/README.md +++ b/README.md @@ -22,15 +22,25 @@ detect the correct handle preceding _DSM and has some built-in safeguards: disabled again if that was the case before suspending. Hibernation should work, but it not tested. -Precautionary measure : -- On some machines, turning off the card is permanent and the card does not - reappear on subsequents reboots, which can result into the screen staying - black all the time, including the BIOS screen. - If it occurs, first try to shutdown, unplug power cord, remove battery, wait - 30s, then put everything back in and boot. If it's not solved, then the - solution is to reset the BIOS to factory settings. Before executing bbswitch - for the first time, it is therefore recommended to take note of the full key - sequence in the BIOS to do a reset. +Preparation +----------- + +### Precautionary measure + +On some machines, turning off the card is permanent and the card does not +reappear on subsequents reboots, which can result into the screen staying +black all the time, including the BIOS screen. +If it occurs, first try to shutdown, unplug power cord, remove battery, wait +30s, then put everything back in and boot. If it's not solved, then the +solution is to reset the BIOS to factory settings. Before executing bbswitch +for the first time, it is therefore recommended to **take note of the full key +sequence in the BIOS to do a reset**. + +### acpi_rev_override + +On some computers (such as the Dell XPS 15 9560, [issue](https://github.com/Bumblebee-Project/bbswitch/issues/148)), you may have to set the `acpi_rev_override` parameter to `1` (`acpi_rev_override=1`). The absence of this parameter may cause a black screen at system boot. + +See [this article](https://wiki.archlinux.org/index.php/Kernel_parameters) for setting and persisting kernel parameters. Build -----