[Skiboot] [PATCH 1/4] fsp/console: Ignore data on unresponsive consoles

Stewart Smith stewart at linux.vnet.ibm.com
Fri Sep 23 16:03:47 AEST 2016

Samuel Mendoza-Jonas <sam at mendozajonas.com> writes:
> On Fri, 2016-07-15 at 15:18 +1000, Stewart Smith wrote:
>> Samuel Mendoza-Jonas <sam at mendozajonas.com> writes:
>> > 
>> > Linux kernels from v4.1 onwards will try to request an irq for each hvc
>> > console using OPAL_EVENT_CONSOLE_INPUT, however because the IRQF_SHARED
>> > flag is not set any console after the first will fail. If there is data
>> > on one of these failed consoles OPAL will set OPAL_EVENT_CONSOLE_INPUT
>> > every time fsp_console_read is called, leading to RCU stalls in the
>> > kernel.
>> > 
>> > As a workaround for unpatched kernels, cease setting
>> > OPAL_EVENT_CONSOLE_INPUT for consoles that we have noticed are not being
>> > read.
>> > 
>> > Signed-off-by: Samuel Mendoza-Jonas <sam at mendozajonas.com>
>> Thanks, merged to master as of fd6b71fcc6912611ce81f455b4805f0531699d5e
>> and 5.2.x as of 7116c948ee63019ceda7dc3b7334e6c25e291eeb
>> This does *slightly* change the API, but it turns out pretty much none
>> of it is documented anyway :/
> Did you have any thoughts on the other three (non-stable) patches of this
> series?

I totally did, and I even got to them today.

merged to master as of 583c820. Also, I may have a crazy plan for crazy
amount of kernel version+OPAL testing as part of op-test-framework now...

Stewart Smith
OPAL Architect, IBM.

More information about the Skiboot mailing list