Muli Ben-Yehuda's journal

Finished the trident TODO by lunchtime today. Patch sent.

Update: whee, Linus responds! (and is 100% correct, as usual).

Finding a bug in your Linux driver via a paper posted on research.microsoft.com hurts my pride. Macros that return are EVIL, damnit!

edit: obviously, I’ve fixed it. I’ll send the patch to Andrew tonight after verifying that it still works.

Talking about signals in Linux sysprogramming class now. trident TODO for today:

– prog_dmabuf takes a rec parameter, make it an ENUM or DEFINE, write two wrappers around it for record / playback.

– SNDCTL_DSP_GETBLKSIZE should probably ‘break’ after checking both files. Verify that other OSS sound drivers behave this way.

– remove the lock_kernel() calls from trident_mmap(), trident_release(). Figure out what it (used to) protect and verify that it’s protected.

– fix the ugly mapped = … line in trident_ioctl()

– verify that the order of cleanup in trident_remove is correct and we can’t take an interrupt when we’re no longer ready to handle it

– in trident_init_module, do we need to unregister a pci driver after registration failed? current code does, verify.

The trident cleanup patch is up. After I got it to compile, there was a nasty buglet were I reworked the error path cleanup in trident_probe(), and ended up doing the cleanup even if the function was successful. Oops. Then, once I got that fixed, playing my test mp3, Abba’s Gimme Gimme, started stuttering. Since I couldn’t figure out why it was happening by just looking at the code, I started unrolling changes, and playing the song again after each change. I must’ve listened to it 50 times by the time I found out the culprit… Abba – it’s not just a band, it’s an occupational hazard of sound drivers developers!

The first day of the Linux sysprogramming class ended up being more interesting than I expected. I used the boring bits to hack on trident, and did a bunch of cleanups I’ve been meaning to do for ages (lock_set_fmt, a macro, was calling return if taking the lock failed. Ugh). I have more plans for tomorrow’s boring parts, but I’ll put up the interim patch in a bit after verifying that it works. It’s currently compiling.

I put up the util-linux tcp-udp nfs mount ordering patch. This patch gives the user greater control over which protocol (TCP or UDP) to use when contacting the NFS server, and whether to fallback to the other one. It’s a bit ugly (mostly because of nfsmount’s ugliness), and I’m waiting to hear what aeb, the maintainer, has to say. While putting it up, I gave the website and especially the CV a much-needed cleanup.

Back to work after a week of military reserve duty, to find two new books waiting for me:
– Linux Kernel Development, by Robert Love
– Unix Systems for Modern Architectures – Symmetric Multiprocessing and Caching for Kernel Programmers, by Curt Schimmel

Yay for new books!

In other news, the weekend was mostly great. On friday ladypine and me went food shopping, and then had a great meal at Spargo accompanied by a bottle of very nice French wine *hic*. Then I met Vered (sister number one) for coffee, and then I spent a few hours setting up the scanner funcionality on Dafna’s (sister number two) HP PSC 2410 printer/scanner, on her Debian unstable system. It works, and I’ll document what I did (why yes, it *did* require a kernel recompilation!) soonish.

On Saturday, ladypine and me went to see LotR. All I can say is that once is definitely not enough. Then we had a quiet weekend at home, had a bit of a fight, discussed many things and reached many conclusions. Then I studied. Small statement, big achievement.

Today I have the first part of a “Linux System Programming” course at work. I daren’t get my hopes too high, but I hope to learn something. At worst (clueless instructor being the worst-case scenario), I’ll pretend to be listening and just hack the kernel all day. Watch this space for my real-time review of the class…

/proc/updike. Is that vulgar, yet silly, or silly, yet vulgar?

… there was a way to see all of the comments posted by a given user? livejournal stalking taken to a whole new level.

Military reserve duty this week. I should be online intermittently. Cheerios, y’all!

My Bytesex Wors entry from earlier is now posted on Oleg’s All Code Sucks page as well. I’m famous!