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Date:   Wed, 30 Dec 2020 18:06:52 +0100
From:   Pali =?utf-8?B?Um9ow6Fy?= <pali@kernel.org>
To:     Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc:     Andrew Lunn <andrew@lunn.ch>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Marek =?utf-8?B?QmVow7pu?= <kabel@kernel.org>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] net: sfp: allow to use also SFP modules which are
 detected as SFF
Message-ID: <20201230170652.of3m226tidtunslm@pali>
References: <20201230154755.14746-1-pali@kernel.org>
 <20201230154755.14746-3-pali@kernel.org>
 <20201230161151.GS1551@shell.armlinux.org.uk>
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On Wednesday 30 December 2020 16:11:51 Russell King - ARM Linux admin wrote:
> On Wed, Dec 30, 2020 at 04:47:53PM +0100, Pali Rohár wrote:
> > Some GPON SFP modules (e.g. Ubiquiti U-Fiber Instant) have set SFF phys_id
> > in their EEPROM. Kernel SFP subsystem currently does not allow to use
> > modules detected as SFF.
> > 
> > This change extends check for SFP modules so also those with SFF phys_id
> > are allowed. With this change also GPON SFP module Ubiquiti U-Fiber Instant
> > is recognized.
> 
> I really don't want to do this for every single module out there.
> It's likely that Ubiquiti do this crap as a vendor lock-in measure.
> Let's make it specific to Ubiquiti modules _only_ until such time
> that we know better.

Ok. This module_supported() function is called in sfp_sm_mod_probe()
function. Current code is:

	/* Check whether we support this module */
	if (!sfp->type->module_supported(&id)) {
		dev_err(sfp->dev,
			"module is not supported - phys id 0x%02x 0x%02x\n",
			sfp->id.base.phys_id, sfp->id.base.phys_ext_id);
		return -EINVAL;
	}

Do you want to change code to something like this?

	/* Check whether we support this module */
	if (!sfp->type->module_supported(&id) &&
	    (memcmp(id.base.vendor_name, "UBNT            ", 16) ||
	     memcmp(id.base.vendor_pn, "UF-INSTANT      ", 16)))
		dev_err(sfp->dev,
			"module is not supported - phys id 0x%02x 0x%02x\n",
			sfp->id.base.phys_id, sfp->id.base.phys_ext_id);
		return -EINVAL;
	}

Or do you have a better idea how to skip that module_supported check for
this UBNT SFP?