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Brad Fitzpatrick

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Linux 2.6, again [Oct. 26th, 2003|01:55 am]
Brad Fitzpatrick
I put Linux 2.6 on my desktop at work out of necessity last week or so (needed ALSA for my sound, and that was already in 2.6), but I just finally got around to putting 2.6 on my home computer. I'd been putting this off because I feared netboot (NFS on root) troubles, after reading on the kernel list ages back that they were gonna drop it, and require users to do in userspace from a RAM disk image, then doing a pivot_root. But, fortunately they didn't remove it, and all went well.

In fact, all went better than well. I observed something pretty odd: The /dev/input/mice which was before just for USB mice now is a generic interface to all mice. I forgot to include USB UHCI support (the config name changed and I didn't notice), so when X started, my mouse worked, except for the scrollwheel. Turns out my BIOS was faking the USB mouse, making it look like a PS/2 device, which the kernel knew about, and reported the events down /dev/input/mice, which my X config was still setup to read. The mouse resolution sucked, but it worked. Rebooted after adding UHCI support and it's all smooth and I can scroll. Very cool.

Half-way through this excercise I justified it as work: all the LJ web nodes netboot in the exact same config as my home computer, so if it works here, the LJ web nodes are ready for 2.6. (which is actually convenient, since epoll is included in 2.6 and we wouldn't have to keep applying patches)

[User Picture]From: scsi
2003-10-26 04:53 am (UTC)
I upgraded my box to 2.6, and for my ps2 mouse to work (even to even receieve power and turn on the optical LED) I had to install the psmouse and the mousedev modules... Very funky.. Before it just "worked" via ps2 for kernel 2.4 without doing anything, but there are modules now for really common low level things like ps2 ports?
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[User Picture]From: mart
2003-10-26 05:46 am (UTC)

Not everyone has PS/2 ports these days. The first things which spring to mind are those “Legacy Free PCs” with only USB ports, but there are also plenty of embedded systems without any “standard” ports at all. Most mice I see on sale today are USB mice with little USB-to-PS/2 adapters in the box, so the trend is clearly away from having a single port dedicated to the mouse.

I think it's nice to make it a module. It means that people without PS/2 ports and the like can easily make their kernel a little smaller. However, it would probably be more sensible to make it be compiled into the kernel by default and turn-offable explicitly in kernel configuration, since you're right that PS/2 ports are incredibly common.

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[User Picture]From: toast0
2003-10-26 11:38 am (UTC)
ps2 mouse support was always optional; although i don't think it was compilable as a module until now.

way back when, nobody had ps2 mice, cause they were all serial, now ps2 mice are under the gun cause peopla want usb instead

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