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

Stewart Smith stewart at linux.vnet.ibm.com
Fri Jul 15 15:18:25 AEST 2016

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 :/

Stewart Smith
OPAL Architect, IBM.

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