user/grub: add arm-smmu.disable_bypass=n quirk for Cavium ThunderX


Bugzilla ID	311
Reporter	Max Rees (sroracle)
Assignee	Max Rees (sroracle)
Reported	2020-06-19 18:50:33 -0500
Modified	2020-06-22 06:03:19 -0500
Status	CONFIRMED
Version	1.0-RC1
Hardware	Adélie Linux / [Community] ARM (64-bit)
Importance	--- / normal
Package(s)	user/grub
See also	https://bugzilla.redhat.com/show_bug.cgi?id=1734557

Description

Linux >= 5.2 contains the following commit, which breaks boot on Cavium ThunderX machines because the Gigabyte devicetree it uses is broken:

We need arm-smmu.disable_bypass=n on these machines.

The "see also" RH bug mentions that iommu.passthrough=1 may also be necessary, but it did not seem needed in order to boot athena.