]> git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/commit
xhci: Workaround to get Intel xHCI reset working more reliably
authorRajmohan Mani <rajmohan.mani@intel.com>
Wed, 18 Nov 2015 08:48:20 +0000 (10:48 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 18 Nov 2015 17:24:41 +0000 (09:24 -0800)
commita5964396190d0c40dd549c23848c282fffa5d1f2
tree2a97d0c81cdc1ecef5ebfbb1838bae55343c13cb
parent53de980796e0b7463dfaa81edc41b272f07b1f17
xhci: Workaround to get Intel xHCI reset working more reliably

Existing Intel xHCI controllers require a delay of 1 mS,
after setting the CMD_RESET bit in command register, before
accessing any HC registers. This allows the HC to complete
the reset operation and be ready for HC register access.
Without this delay, the subsequent HC register access,
may result in a system hang, very rarely.

Verified CherryView / Braswell platforms go through over
5000 warm reboot cycles (which was not possible without
this patch), without any xHCI reset hang.

Signed-off-by: Rajmohan Mani <rajmohan.mani@intel.com>
Tested-by: Joe Lawrence <joe.lawrence@stratus.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/usb/host/xhci.c