diff options
author | Ben Guthro <benjamin.guthro@citrix.com> | 2013-04-24 11:41:53 +0200 |
---|---|---|
committer | Jan Beulich <jbeulich@suse.com> | 2013-04-24 11:41:53 +0200 |
commit | 6e96c186d23873597896051b043cfeb119c4a7d5 (patch) | |
tree | 28cf07f1300be3a5a56d0764f3cbaf9927a6cf74 /tools/hotplug | |
parent | 3f28d0077788e7f8cd3ee25b023a4225d7e26e87 (diff) | |
download | xen-6e96c186d23873597896051b043cfeb119c4a7d5.tar.gz xen-6e96c186d23873597896051b043cfeb119c4a7d5.tar.bz2 xen-6e96c186d23873597896051b043cfeb119c4a7d5.zip |
ns16550: delay resume until dom0 ACPI has a chance to run
Check for ioport access, before fully resuming operation, to avoid
spinning in __ns16550_poll when reading the LSR register returns 0xFF
on failing ioport access.
On some systems (like Lenovo T410, and some HP machines of similar vintage)
there is a SuperIO card that provides this legacy ioport on the LPC bus.
In this case, we need to wait for dom0's ACPI processing to run the proper
AML to re-initialize the chip, before we can use the card again.
This may cause a small amount of garbage to be written to the serial log
while we wait patiently for that AML to be executed.
This implementation limits the number of retries, to avoid a situation
where we keep trying over and over again, in the case of some other failure
on the ioport.
Signed-Off-By: Ben Guthro <benjamin.guthro@citrix.com>
Acked-by: Keir Fraser <keir@xen.org>
Diffstat (limited to 'tools/hotplug')
0 files changed, 0 insertions, 0 deletions