From: "Bjørn Mork" <bjorn@mork.no>
To: Andrew Lunn <andrew@lunn.ch>
Cc: M Chetan Kumar <m.chetan.kumar@intel.com>,
netdev@vger.kernel.org, linux-wireless@vger.kernel.org,
johannes@sipsolutions.net, krishna.c.sudi@intel.com
Subject: Re: [PATCH 17/18] net: iosm: readme file
Date: Sun, 17 Jan 2021 18:26:54 +0100 [thread overview]
Message-ID: <87turftqxt.fsf@miraculix.mork.no> (raw)
In-Reply-To: <X/eJ/rl4U6edWr3i@lunn.ch> (Andrew Lunn's message of "Thu, 7 Jan 2021 23:23:58 +0100")
Sorry about being much too late into this discussion. I'm not having
the bandwidth to read netdev anymore, and just stumbled across this now.
Andrew Lunn <andrew@lunn.ch> writes:
> So, this is what all the Ethernet nonsense is all about. You have a
> session ID you need to somehow represent to user space. And you
> decided to use VLANs. But to use VLANs, you need an Ethernet
> header. So you added a bogus Ethernet header.
Actually, the original reasoning was the other way around.
The bogus ethernet header was added because I had seen the 3G modem
vendors do that for a few years already, in the modem firmware. And I
didn't think enough about it to realize that it was a really bad idea,
or even that it was something I could change. Or should change.
I cannot blame the MBIM sesison to VLAN mapping idea on anyone else. As
far as I can remember, that was just something that popped up in my head
while working on the cdc_mbim driver. But it came as a consequence of
already having the bogus ethernet header. And I didn't really
understand that I could define a new wwan subsystem with new device
types. I thought I had to use whatever was there already.
I was young and stupid. Now I'm not that young anymore ;-)
Never ever imagined that this would be replicated in another driver,
though. That doesn't really make much sense. We have learned by now,
haven't we? This subject has been discussed a few times in the past,
and Johannes summary is my understanding as well:
"I don't think anyone likes that"
The DSS mapping sucks even more that the IPS mapping, BTW. I don't
think there are any real users? Not that I know of, at least. DSS is
much better implmeneted as some per-session character device, as
requested by numerous people for years. Sorry for not listening. Looks
like it is too late now.
> Is any of this VLAN stuff required by MBIM?
No. It's my fault and mine alone.
> I suggest you throw away the pretence this is an Ethernet device. It
> is not.
I completely agree. I wish I had gone for simple raw-ip devices both in
the qmi_wwan and cdc_mbim. But qmi_wwan got them later, so there is
already support for such things in wwan userspace.
Bjørn
next prev parent reply other threads:[~2021-01-17 17:29 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-07 17:05 [PATCH 00/18] net: iosm: PCIe Driver for Intel M.2 Modem M Chetan Kumar
2021-01-07 17:05 ` [PATCH 01/18] net: iosm: entry point M Chetan Kumar
2021-01-07 17:05 ` [PATCH 02/18] net: iosm: irq handling M Chetan Kumar
2021-01-07 17:05 ` [PATCH 03/18] net: iosm: mmio scratchpad M Chetan Kumar
2021-01-07 17:05 ` [PATCH 04/18] net: iosm: shared memory IPC interface M Chetan Kumar
2021-01-07 17:05 ` [PATCH 05/18] net: iosm: shared memory I/O operations M Chetan Kumar
2021-01-07 17:05 ` [PATCH 06/18] net: iosm: channel configuration M Chetan Kumar
2021-01-07 17:05 ` [PATCH 07/18] net: iosm: char device for FW flash & coredump M Chetan Kumar
2021-01-07 19:35 ` Andrew Lunn
2021-01-07 17:05 ` [PATCH 08/18] net: iosm: MBIM control device M Chetan Kumar
2021-01-07 17:05 ` [PATCH 09/18] net: iosm: bottom half M Chetan Kumar
2021-01-07 17:05 ` [PATCH 10/18] net: iosm: multiplex IP sessions M Chetan Kumar
2021-01-07 17:05 ` [PATCH 11/18] net: iosm: encode or decode datagram M Chetan Kumar
2021-01-07 21:56 ` Andrew Lunn
2021-01-07 17:05 ` [PATCH 12/18] net: iosm: power management M Chetan Kumar
2021-01-07 17:05 ` [PATCH 13/18] net: iosm: shared memory protocol M Chetan Kumar
2021-01-07 17:05 ` [PATCH 14/18] net: iosm: protocol operations M Chetan Kumar
2021-01-07 17:05 ` [PATCH 15/18] net: iosm: uevent support M Chetan Kumar
2021-01-07 17:05 ` [PATCH 16/18] net: iosm: net driver M Chetan Kumar
2021-01-07 20:11 ` Andrew Lunn
2021-01-07 17:05 ` [PATCH 17/18] net: iosm: readme file M Chetan Kumar
2021-01-07 22:23 ` Andrew Lunn
2021-01-15 9:15 ` Johannes Berg
2021-01-17 17:26 ` Bjørn Mork [this message]
2021-01-20 19:34 ` Andrew Lunn
2021-01-20 23:32 ` Jakub Kicinski
2021-01-21 1:34 ` Dan Williams
2021-01-22 23:45 ` Andrew Lunn
2021-01-07 17:05 ` [PATCH 18/18] net: iosm: infrastructure M Chetan Kumar
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