jcm's blog

My current flight itinerary for December (updated as it changes):

UA9230 LHR (2005/12/15 11:05) -> MUC (2005/12/15 13:50)
UA8871 MUC (2005/12/15 15:15) -> JFK (2005/12/15 18:25)
UA21 JFK (2005/12/19 08:00) -> SFO (2005/12/19 11:21)
UA886 SFO (2005/12/19 12:11) -> LAX (2005/12/19 13:30)
UA304 LAX (2005/12/20 13:45) -> SFO (2005/12/20 15:06)
UA830 SFO (2005/12/24 10:55) -> ORD (2005/12/24 17:10)
UA7690 ORD (2005/12/24 17:45) -> YUL (2005/12/24 20:54)
AC706 YYZ (2005/12/29 10:15) -> LGA (2005/12/29 11:40)
UA8840 JFK (2005/12/29 16:05) -> FRA (2005/12/30 05:30)
UA8809 FRA (2005/12/30 07:25) -> LHR (2005/12/30 08:05)


Train itinerary (updated as it changes):

VIA33 Montreal (2005/12/26 10:00) -> Ottawa (2005/12/26 11:39)
VIA43 Ottawa (2005/12/28 08:40) -> Toronto (2005/12/28 13:00)


I went to The Orange Tree in Richmond yesterday afternoon to see Three in the back, two in the head, an interesting small theatre production concerning the events surrounding the cold war and the Star Wars project. I went with one of the London meetup groups I have joined. It’s a cool way of hanging out with Canadians and other North Americans as well as various other interesting people. Hopefully, we’ll organise a trip to Snowdon for January. Actually the social thing is fun – I’m hanging out with the local climbing group a bit more now too. I went along on Thursday evening and tried solving a few problems the guys were making up, but I need to go to the gym more often if I’m going to hope to keep up with Dan and Stefan.

Figure: North America trip, December 2005.

I’m going to be hooking up with Bill for a few days in December, so I’ve got to book some more flights within the US. In an ideal world where I sort out my full itinerary soon, then I’ll fly via Los Angeles so I can hook up with Daniel while he’s simultaneously on vacation – and can then potentially swing by Anaheim for some coffee. I’m booked to fly into NYC on Dec 15 and then must go and see Washington D.C. (the Smithsonian in particular) before Christmas. I’m also expecting to take a train to Boston (in the US trains seem to run mostly in the mornings between these places so I have a choice of crashing in a hotel or taking the late coach back – depends on the price) and will then fly over to San Francisco for a few days. I’ll then take a train from NYC to Montreal and hang out with Eric, before going on to Ottawa. I haven’t decided yet whether I can really fit in going to Halifax this time, but I’d like to.

IBM sent me an OpenPower 710 to play around with. It’s nice and heavy and filled with 64-bit goodness. I’ll use it to test things for the book and to play around with the hardware virtualisation support under Linux. Now that I’ve got some decent POWER5 kit I can actually hack on the ppc64 tree a little. My floppy patch from before turned out to need a fix which exposed some other problems in the floppy driver I need to look at – in fact there’s a whole bunch of stuff I should help to fix.

The Wall Street Journal called me up last week as a source for an article on Ottawa. I had more than a few nice things to say about the place and why everyone should go visit.

Jon.

According to Google News, voters did pass the gun ban law I mentioned last week. Unfortunately, it’s looking doubtful that it will come to fuition because:

• A similar law in 1982 was overturned as pre-empted by State law.
• The NRA and gun toting second amendment nuts are out in force.

That’s a shame. As I said before, I really grok the reasoning people have for owning guns and really grok the dangerous uses they have. I generally don’t like repressive laws but in this case the voters (the people) have decided they don’t want guns – and if the people wanted guns again then they could get another bill put before the legislature.

I doubt very much that they’ll see sense. There are too many people saying it’s a bad thing for this ban to last very long. I wouldn’t pass legislation against owning handguns anyway, I’d simply go for the aggressive taxation approach. Just like for tobacco, if we made it so prohibitively expensive for anyone to smoke or own guns then the problems would soon improve.

[ED: I don't mean that we currently have high tobacco taxes. I'm talking super taxation. ]

Jon.

The DMA generic handling code for ppc4xx is broken. This is apparently well known enough that nobody is relying upon it. I learned this the hard way when implementing DMA to/from NAND flash MTD devices. Here’s a handy hacker’s guide to doing it right. The key thing is to not rely on any of the generic routines and to do direct setup of the DMA engine for yourself. To configure channel 2 (numbers in brackets correspond to the datasheet):

mtdcr(DCRN_DMACR2, 0);
/* 1. Set the transfer width: */
mtdcr(DCRN_DMACR2, SET_DMA_PW(PW_8));
/* 2. Source Address: */
mtdcr(DCRN_DMASA2, source_address);
/* 2. Destination Address: */
mtdcr(DCRN_DMADA2, destination_address);
/* 3. Set Count: */
mtdcr(DCRN_DMACT2, len);
/* 4. Clear Status: */
mtdcr(DCRN_DMASR, DMA_CS2|DMA_TS2|DMA_CH2_ERR);
/* Source Increment: */
mtdcr(DCRN_DMACR2, mfdcr(DCRN_DMACR2) | SET_DMA_SAI(0));
/* 5. Destination Increment: */
mtdcr(DCRN_DMACR2, mfdcr(DCRN_DMACR2) | SET_DMA_DAI(1));
/* 5. Software memory-to-memory: */
mtdcr(DCRN_DMACR2, mfdcr(DCRN_DMACR2) | SET_DMA_TM(TM_S_MM));
/* 5. Interrupt Enable: */
mtdcr(DCRN_DMACR2, mfdcr(DCRN_DMACR2) | SET_DMA_CIE_ENABLE(1));
mtdcr(DCRN_DMACR2, mfdcr(DCRN_DMACR2) | SET_DMA_PL(EXTERNAL_PERIPHERAL));
mtdcr(DCRN_DMACR2, mfdcr(DCRN_DMACR2) | SET_DMA_ETD(1)); /* 1 req. */
mtdcr(DCRN_DMACR2, mfdcr(DCRN_DMACR2) | SET_DMA_TCE(1)); /* 1 req. */

To display the configuration:

printk("DMA Configuration:\n\n");
printk("DCRN_DMACR2=0x%08x\n", mfdcr(DCRN_DMACR2));
printk("DCRN_DMASA2=0x%08x\n", mfdcr(DCRN_DMASA2));
printk("DCRN_DMADA2=0x%08x\n", mfdcr(DCRN_DMADA2));
printk("DCRN_DMACT2=0x%08x\n", mfdcr(DCRN_DMACT2));
printk("DCRN_DMASR=0x%08x\n", mfdcr(DCRN_DMASR));

To enable the operation:

mtdcr(DCRN_DMACR2, mfdcr(DCRN_DMACR2) | SET_DMA_CE_ENABLE(1)); /* 5. Channel enable */


Sit and wait on an completion and have the interrupt handler also do this:

mtdcr(DCRN_DMASR, DMA_CS2|DMA_TS2|DMA_CH2_ERR); /* zero status */


Apprently, there’s talk of a generic DMA abstraction, which would be nice. I’m keen to help out with that once I get back onto playing with 2.6 proper.

I spent a bit of time over the weekend tidying up odds and ends on the magazine and doing some other writing. I’ve received an advance on the book now (and figured out how to pay a dollar cheque into my bank – that was fun) and am officially writing. Not that I’ve gotten very far yet but the important thing is I’ve at least started trying to make some progress. I’ve also written a bunch of other stuff and started reading more Bill Bryson. I’ve developed a morning routine of having coffee, a pasty, reading a bit of my book and catching up with The Independent. That’s a quality newspaper. I was shocked yesterday to discover that as of January all offences will become arrestable under law (no matter how trivial) and today they’re doing a good job of bashing Blair over the 90 day terror detention crap.

Jon.

San Francisco voters will decide on Tuesday whether to ban the sale and posession of hand guns within city limits. This is good news, for a variety of reasons but on the whole will do little to impact upon the horrifying national gun crime statistics for the United States as a whole. See, I believe on a fundamental level that I should have a right to bear arms (I don’t in the UK in general) but I’m really glad we don’t allow just anyone to walk in off the street and buy a gun so they can go postal with it. If it weren’t for the fact that the US doesn’t implement gun control in a sane fashion and that you’re statisically far more likely to accidentally kill one of your family members than defend against a would-be burglar then I might understand the realities of a country which still believes it necessary for people to own guns to prevent the government from being too powerful. While it’s quaint that the constitution provides for this measure, they didn’t have nukes back then or big insane guns that exist today – the average person aint gonna take on the US government and win any more so quit with that rhetoric already.

Still, in the UK, it’s the first day of the first hunting season after the ban on fox hunting. There are still a few insane whackjobs out there trying to exploit loopholes or just ignore the law completely (because they believe that cruelty to animals is an acceptable side effect of their “sport”) but hopefully they’ll slowly be convinced that it’s no longer acceptable in society. I really do feel for those people losing livelihoods over the whole thing, but in much the same way that the tabacco industry is going to suffer, I think it’s right in the end. I would like to see more government provision for these people to retrain in less callous endevaours however.

Jon.

I just got back from speaking at a migration event in Manchester, organised by the folks at IBM. This was the first time I have spoken at one of their events and I got to give an overview of the Linux and Power communities, our history, and where we are going forward. I also got to meet a bunch of people and apparently will have my own POWER5 box turning up for development. I also enjoyed being put up in the Radisson for a night and having the chance to sync up with Jono and some of the other guys who I don’t see all too often.

I’ve booked some flights for December:

UA9230 LHR (2005/12/15 11:05) -> MUC (2005/12/15 13:50)
UA8871 MUC (2005/12/15 15:15) -> JFK (2005/12/15 18:25)
UA8840 JFK (2005/12/29 16:05) -> FRA (2005/12/30 05:30)
UA8809 FRA (2005/12/30 07:25) -> LHR (2005/12/30 08:05)

I’ll take the train to Montreal and then swing by Ottawa for a few days. I haven’t yet decided whether I’m going out to Halifax and I’d also like to go and see the District of Columbia for a few days too. Those are logistics that I’ll need to sort out over the next month.

I had lunch with John Buckman earlier and then swung by his pad in Covent Garden for some coffee and an interview. He’s one seriously cool guy and really seems to understand the issues involved in doing online music right. I’ve even discovered a couple of new Canadian artists that I didn’t know about before.

This evening, I had a wonder around the market at Covent Garden, had yet more blueberry juice and found yet another specialist tea shop that doesn’t have Maple Tea (one of the folks at Whittard has however agreed to pass on some for tasting if I pick some up). I found an outdoor store on the corner and bought a belay plate and caribiner. Tonight, I bought some more music on John’s website and dropped Brad Sucks a line (since he’s from Ottawa and I like supporting Canadian artists). My day started with a courier rush pickup and ended with impulsive music purchasing.

Jon.

I went along to a bunch of tonight’s Meetup events at a bar in High Holborn. These were formed from an amalgam of several different groups, including the Americans Abroad, Canadian London Expats, and various others. I met some fun people (including at least one who had also travelled in from Reading) and will probably swing by next time around.

Jon.

Has anyone else noticed how middle clicking on recent builds of Debian abiword causes it to decide that it doesn’t want to paste your text but instead will crash randomly and lose your document? If there’s any one single thing which will put people off using Linux then it’s wordprocessors which will crash without warning or without any option to gracefully exit. Please fit it guys.

I’ll fire it up under gdb when I get chance, but I’ll likely have to rebuild the whole damned thing with debugging symbols to get anything useful other than a memory reference.

Jon.