sis module / graphics card

Dear Sir or Madam,

I am using a laptop, Acer Aspire 3634 WLMi, with a SiS M661MX as graphics card. When I install FreeBSD 6.2 its display is working at the correct resolution, 1280x800 (and I think 1280x768 is possible, too). I am using the "sis generic" driver.

However, when I tried to install FreeBSD 6.3, 6.4 and 7.1, I cannot any more select the sis generic driver. If I do so, I get a message that the module could not be found. If I then try to run X with the driver "generic vesa compatible", I am unable to get a resolution matching the native resolution of my screen: It looks as if the screen is in horizontal stripes, periodically getting more resolution and less resolution. This is very annoying when trying to read any text.

I must say, similar problems I experienced also in NetBSD 4.x. Just there, the screen just stays black if I select sis as driver. If I select generic vesa compatible, again, I get an uneven resolution.

Linux (Ubuntu 6.x, 7.x and 8.04) did not show such problems and displays my native resolution.

Given that FreeBSD 6.2 works (as did 6.1), and that the later versions complain about the lack of the sis module, I assume that something has happened with the sis module.

My question therefore is: How can I get the correct screen resolution in FreeBSD 6.4? Do I have to get a module for sis, and if so, from where?

Kind regards,


P.S.: Please forgive me if this information is not expressed in all technical details, but I switched to Linux for as long as the problem persists.
That is precisely the point. I did NOT have a sis driver, as far as I could tell. I have no idea why, in 6.2 I had it. The driver of 6.2 was not accepted in 6.3. I read that for some reason, the driver had not been included in the CD distribution, I should try to install over FTP... I did, no success - again no driver. So, where can I find a driver? (And why has it been omitted in the first place?!)