Hi,

On Mon, Jun 20, 2016 at 10:44:55AM -0700, Brian Norris wrote:

On Mon, Jun 20, 2016 at 09:46:57AM -0400, Javier Martinez Canillas wrote:

quoted

On 06/18/2016 01:09 PM, Guenter Roeck wrote:

quoted

On 06/17/2016 06:08 PM, Brian Norris wrote:

quoted

How do you propose we do that? Do all of the following become EINVAL?

Yes, I would just do that.

The idea of this helper is to remove duplicated code and AFAICT what most EC
drivers do is something similar to the following:

        ret = cros_ec_cmd_xfer(ec, msg);
        if (ret < 0)
	   	return ret;

        if (msg->result != EC_RES_SUCCESS) {
                dev_dbg(ec->dev, "EC result %d\n", msg->result);
                return -EINVAL;
        }

So in practice what most drivers really care is if the result was successful
or not, I don't see specific EC error handling in the EC drivers.  The real
EC error code is still in the message anyways so drivers that do cares about
the real EC error can look at msg->result instead.

[...]

quoted

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         EC_RES_INVALID_COMMAND

    -EOPNOTSUPP

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         EC_RES_INVALID_PARAM

    -EINVAL or -EBADMSG

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         EC_RES_INVALID_VERSION

    -EPROTO or -EBADR or -EBADE or -EBADRQC or -EPROTOOPT

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         EC_RES_INVALID_HEADER

    -EPROTO or -EBADR or -EBADE

Doesn't look that bad to me. Also, the raw error could still be logged,
for example with dev_dbg().

Yes, I think that adding a dev_dbg() with the real EC error code should
be enough, that's basically what drivers do since they can't propagate
the EC error to higher layers anyways.

I'll take a look at adding an error code translation table when I get a
chance. Hopefully that doesn't delay the others who are planning to use
this API shortly...

Actually, I had some second thoughts, and others brought similar
concerns up to me:

What do we really win by doing the translation? It'll be difficult to do
a 1:1 translation, and any time the EC adds additional error types,
we'll have to update the translation. What's more, AFAICT, no one will
really be looking at the translated error codes now, and will just be
blindly passing them on. So maybe it makes more sense to just pick a
single error code and pass that on instead. Possibly just -EPROTO (or
nominate your favorite) for all EC error results, and if someone cares,
they decode msg->result in their driver, or check the dev_dbg() log?

Brian