Date: Wed, 24 Nov 2010 22:20:39 +0100 From: Ulrich =?utf-8?B?U3DDtnJsZWlu?= <uqs@spoerlein.net> To: Peter Jeremy <peterjeremy@acm.org> Cc: stable@freebsd.org, freebsd-arch@freebsd.org Subject: Are there digi(4) users running -STABLE? (was Re: Migrating ISA/PCI drivers) Message-ID: <20101124212039.GL3120@acme.spoerlein.net> In-Reply-To: <20101118222100.GA47116@server.vk2pj.dyndns.org> References: <20101118222100.GA47116@server.vk2pj.dyndns.org>
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[cross-posting to stable@, where some of those folk might hang out] On Fri, 19.11.2010 at 09:21:00 +1100, Peter Jeremy wrote: > I'm (belatedly) looking at porting digi(4) to the MPSAFE TTY system > and have some architectural questions. > > The digi(4) driver appears to support 5 different Digi card variants, > at least two of which exist in both ISA and PCI variants. Looking at > the Digi website, it appears that both PCI and ISA cards are still > available (as well as a PCIe card which is unlikely to work with the > current driver). I only have access to PCI/Xem cards and so can't > test my changes on any other card types. I presume Digi cards are not > that popular because noone else has shown any interest in the driver > since the MPSAFE TTY changes were announced about 2.5 years ago. > > How much effort should I invest in adapting code for other card types? > In particular, the ISA cards use windowed memory accesses and IO ports > where the PCI cards have a single flat memory aperture. Removing > support for ISA cards would simplify the code (and remove the need to > make decisions about whether I need to do window switches in new > code), as well as potentially allowing finer grained locks. > > My options would seem to be: > 1) Rip out the ISA support - this is the cleanest for me but maximises > effort for a future person wanting to support ISA Digi cards. > 2) Carry forward the ISA code as best I can and ensure new code includes > appropriate window switches etc. This maximises my effort but > hopefully makes it easier for someone to get ISA cards working. > 3) Ignore the ISA code. This is fairly easy but probably requires > similar effort to (1) to get it going on ISA since all the code > would need to be reviewed to add necessary ISA-specific locking/ > window switching. > > My preference is 1 since it leaves the least cruft (from my point of > view) in the code and doesn't give users the false impression that > ISA cards work. > > I would appreciate some advice on the best way forward. In the > absence of any input, I will probably stick with option 3 for now but > may move to option 1 if the ISA code starts getting in the way. Keep > in mind that digi(4) does not currently compile on FreeBSD-8 or later, > so any of the above options are an improvement over the status quo, > though all are a regression from FreeBSD-7. > > Of course, if someone has access to other Digi card types and wants > to assist with porting and testing, I would be happy to work with them. > > -- > Peter Jeremy
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