[Skiboot] [PATCH] hw/port80: Squash No SYNC error

Stewart Smith stewart at flamingspork.com
Fri Oct 18 17:36:04 AEDT 2019

> On 17 Oct 2019, at 21:30, Oliver O'Halloran <oohall at gmail.com> wrote:
> On Aspeed BMCs can be configured to route LPC IO address 0x80 to a GPIO
> port. Some systems use this to implement a boot progress indicator, but
> not all of them.
> There's no easy way to tell if this has been setup or not and if it
> hasn't we get an LPC SYNC no-response error from out LPC master. When we
> reach Linux and enable interrupts this results in this spurious error
> being printed:
>    LPC[000]: Got SYNC no-response error. Error address reg: 0xd0010082
> lpc_probe_write() is intended to catch situations where the peripherial
> being written to might not be configured, so use that instead of
> lpc_outb() to squash the error.
> Cc: Ranga <stewart at flamingspork.com>
> Cc: Andrew Jeffery <andrew at aj.id.au>
> Signed-off-by: Oliver O'Halloran <oohall at gmail.com>
> ---
> Stewart, do you know what systems actually implment this feature?
> Seem like you added op_display_lpc() to add the BMC systems, but
> I'm guessing only a few of them actually support it.

All the Raptor systems do, and the code has (IIRC) headed upstream to OpenBMC.

Maybe should just silence the error on other systems? That was the original thought, nothing there listening = silence any error 

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