Muli Ben-Yehuda's journal

December 11, 2006

Filed under: Uncategorized — Muli Ben-Yehuda @ 9:55 AM

10/12/06 – the big news is that CalIOC2 DMAs are now going through!
the HW guys hooked up a logic analyzer and figured out that Linux is
misprogramming the bridge to have a base/limit of 0/0, which caused a
nasty interaction with the 0-1MB MMIO region on the bridge, since TCE
addresses are allocated from 0 and up. The
workaround is simple, start allocating TCEs from address 1MB and up,
and voila, DMAs start coming through.

I’m now trying to
understand why Linux is misprogramming the bridge. It only happens
when TCEs are enabled, and a diff of dmesg from the same kernel with
TCEs enabled and disabled has this to say:

+PCI: Ignore bogus resource 7 [0:0] of 0000:0a:00.0 
+PCI: Ignore bogus resource 8 [0:0] of 0000:0a:00.0
 PCI: Bridge: 0000:0a:00.0
-  IO window: disabled.
-  MEM window: disabled.
+  IO window: 0000-0000
+  MEM window: 00000000-00000000
   PREFETCH window: d4100000-d41fffff

After I figure this one out, I need to implement a new cache flush
routine for CalIOC2 and another workaround the designer recommends,
stress test it, and then if all goes well it can go in, probably for

In other news, my hacker’s diet and workout regime is working very
well. I’m losing weight at a steady rate of 0.6kgs per week and
feeling better every day. Starting the day with a walk on the
sea-shore before the sun rises, masochistic as it may be, is also
highly enjoyable. The more I suffer, the more I enjoy it. I’m going to
add swimming too next week, albeit in a heated pool, not in the cold

In other other news, we decided to go ahead with the USENIX
paper. Deadlines, here we come!


  1. > “Starting the day with a walk on the sea-shore before the sun rises,
    > masochistic as it may be, is also highly enjoyable.”
    > Sounds insane, But very cool. I’ve noticed that about Aikido as well. We like
    > hurting ourselves for benefit.
    You are most welcome to join… the bus leaves at 0525 in the morning and we walk or jog from the end of the boardwalk to the 2kms marker and back.
    > Sarah’s dad has been on an intense diet these past months. He has so far
    > lost 10% of his body weight. He looks and feels better. As an analytical
    > chemist, he has taken measuring his body weight way-way too far, as only a
    > man with a new hobby can (spreadsheets, scatter plots, recording his weight
    > before and after bowel movements…).
    I have the spreadsheet, the moving averages and the pretty graphs (via the afore-mentioned hacker’s diet tracker), but I only get weighed once a day in the morning. I can certainly understand the attraction of MORE DATA.
    > He also mentioned that people tell him that once you reach a loss of 10% of
    > your body weight you have to stop, and try to maintain that for at least 5
    > years.
    10% is nothing… 🙂

    Comment by mulix — December 11, 2006 @ 2:58 PM | Reply

  2. Usenix paper?
    You meant the Annual Technical Conference of Usenix? You have almost 1 month to work on that 🙂

    Comment by Anonymous — December 13, 2006 @ 12:09 AM | Reply

  3. Joy of Effort
    As a philosopher, I am currently studying why we enjoy putting forth physical effort. I have my research in order, save interviews from people who have noticed the phenomenon in their own experiences. In lieu of interviews, it would be fun to read as you expound upon how and why you enjoy putting forth effort. Is it the fruits of the effort that make you enjoy the effort, or is it merely the physiological response as an effect of the act itself (chemicals flooding the brain as a result of physical activity?) I’ll accept any thoughts you have, even if you haven’t given it much thought yet. Develop your own reasoning over time, update us once in a while, and tell me why you enjoy effort.

    Comment by alpha_unit — December 22, 2006 @ 12:14 PM | Reply

  4. Depressing, ain’t it?

    Comment by Anonymous — April 18, 2007 @ 11:06 AM | Reply

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