Re: [RFC PATCH net-next 3/3] net/mlx5e: Expose link down reason to ethtool

On Thu, 22 Jun 2017 11:33:39 +0300, Gal Pressman wrote:

quoted

quoted

Is my reading correct that in case the reason is not in the
pddr2ethtool_table opaque binary data will be passed from the firmware
to user space?  Is there any particular reason to allow for this?  If
it's just for the rare scenario where a new error code needs to be
added perhaps it would be enough to dump the FW-provided message to the
logs?  

No binary data is passed in this patch, the monitor_opcode is simply a vendor specific
16 bit id that is used when the reason  is not generic enough to have it's own enum.

Sorry if I'm wrong, I thought this would potentially copy
ETH_GSTRING_LEN bytes to userspace:

+	if (status_message)
+		memcpy(status_message,
+		       MLX5_ADDR_OF(pddr_reg, out, page_data.troubleshooting_info_page.status_message),
+		       ETH_GSTRING_LEN);

I'm also still not sure why a reason would not be generic enough for
the enum, if it fits in the 16bit vendor enum... 

Some reasons might be very specific, and only relevant to my hardware for example.
In that case I'd like to avoid an enum entry that is not wide enough to be used by anyone else but me,
and still have a way to pass it to the user.

The userspace patches will allow for a vendor parser (similar to ethtool regdump parsers) that can
convert this 16bit id to a string.