Re: staging status of rts_pstor and rts5139

[Don Zickus <dzickus@redhat.com>]

On Mon, Feb 13, 2012 at 03:01:23PM -0500, Chris Ball wrote:
> Hi Don,
> 
> On Mon, Feb 13 2012, Don Zickus wrote:
> > Hi Chris,
> >
> > My name is Don Zickus from Red Hat.  I am working with a vendor that would
> > like to ship hardware that requires the rts_pstor and rts5139 drivers (two
> > different hardware platforms).  Before we include them in our RHEL OS, we
> > would like to figure what is needed to bump those drivers from 'staging'
> > status to something the linux-mmc community would fully support.  Is there
> > a lot of work to be done or just some style cleanups?  Or perhaps you
> > haven't really looked at them yet.
> 
> I have had a chance to look at rts_pstor: it's awful, I'm afraid.  It
> emulates a SCSI device out of the PCI card reader, and it embeds its
> own copy of an SD stack inside the driver (in sd.c) behind the scenes
> instead of using the kernel's drivers/mmc stack, which is not acceptable.
> I don't think there's any future for the driver in mainline until these
> complaints are changed; it probably shouldn't even be in staging.
> 
> So, I think that for it to be merged, it must first be rewritten to be
> a driver that's a few hundred lines long -- instead of 20,000! -- that
> (a) uses Linux's SD stack and (b) exposes MMC devices, not SCSI ones.
> That's a fairly complete rewrite, unfortunately, and would only cover
> the MMC/SD interface on the hardware -- the same hardware supports
> memorystick and xD too, which are different standards/subsystems.
> 
> I had not looked at rts5139, but just took a quick look and it seems
> like it's an unmerged duplicate fork of the rts_pstor driver -- another
> 20k lines, mostly the same as the ones in rts_pstor, of SCSI emulation
> and bundled SD stack, so all of my comments would apply to it too.
> 
> Sorry I don't have better news!  I think your best option for mainline
> support would be to find a way to offer a long-term loan of systems with
> this hardware inside to any volunteers from linux-mmc@ who want to work
> on a replacement driver for it; I asked Dell for the same when I learned
> they were shipping these devices in laptops, but they don't seem to be
> able to loan out laptops for more than a couple of weeks.  I did start
> out on an rts_pstor rewrite, but wasn't able to get it working before
> my temporary access to the hardware ran out.
> 
> (I do wish there were better relationships between the kernel community
> and people with new hardware that needs support added for it, such that
> we could just file a request with Red Hat, Lenovo or Dell to get access
> to shipping hardware with some new chip..)

Thanks for the quick reply.  I was wondering why the driver seemed so
large and now it makes sense.  Don't worry about the bad news, it might
give us leverage. :-)

Your point about hardware access makes sense, though I don't expect it to
come out very favorably, I'll poke some people about how to get better at
leveraging things for the community.

Thanks for your time!

Cheers,
Don