Re: Firmware versioning best practices: ath3k-2.fw rename orreplace ath3k-1.fw ?

From: Senthil Balasubramanian
Date: Mon Oct 11 2010 - 03:14:16 EST


On Sat, Oct 09, 2010 at 01:31:28PM +0530, Marcel Holtmann wrote:
> Hi Luis,
>
> > What is the difference between ath3k-2.fw and ath3k-1.fw ?
> >
> > Won't the API change now that you are addressing the sflash
> > configuration fix? Would it not help to identify the two
> > different firmwares then?
> >
> > David, Marcel, what are your preferences for a firmware upgrade
> > where the firmware does not change API (lets just pretend it does
> > not for a moment) ? Do we keep the same filename?
>
> that is what most companies do and that is what iwlwifi has done so far.
Luis

this is what we have been doing for our ath9k_htc driver. We kept the same
fie name for firmware updates as we haven't changed any APIs/interfaces that
host driver depends on.

> Only if the API breaks a different suffix is used.
>
> With Bluetooth this should be never needed at all. The reason is that
> you need to expose Bluetooth HCI. And that has generic version, support
> commands and supported features commands.
>
> We are not even using the version information for anything useful these
> days since the firmware has to identify its features and its supported
> commands with standard HCI commands. So it is pretty simple to detect
> what Bluetooth subsystem needs to do.
>
> > In this particular case I would assume our new sflash configuration
> > fix that might be being worked on might change the re-enumerated
> > USB device IDs so it seems to me a good idea to use a new filename.
> > I should note ath3k-2.fw already made it to linux-firmware.git...
>
> No it does not. The changed PID is not a breakage. It will just keep
> working. So please fix this in linux-firmware.git right away and remove
> the new firmware file.
>
> And here is something that is wrong with your process as well. Don't
> submit firmware files upstream before the upstream maintainers accepted
> your driver or patch.
>
> I know it is nice to have the firmware available quickly, but if your
> driver gets rejected for the reason we have stated in this thread, you
> have dangling firmware somewhere.
>
> > I last tried to document a thread we had over this here:
> >
> > http://wireless.kernel.org/en/developers/Documentation/firmware-versioning
> >
> > Does this sound sane? If so then the sflash configuration fix
> > would seem to me like it would require a new filename. Now, while
> > we're at it, how about bug fixes?
>
> If your firmware files are identical and the exposed API is identical
> (in this case Bluetooth HCI), then you do NO need a new filename.
>
> Regards
>
> Marcel
>
>
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