Messages in this thread | | | Date | Sun, 12 Feb 2006 18:26:08 +0100 | From | Pavel Machek <> | Subject | Re: [PATCH] [RESEND] Add Dell laptop backlight brightness display |
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Hi!
> You can get and set laptop brighness on Dell with the proper SMI call. > > To do the proper SMI call requires parsing SMBIOS structure 0xDA, a > vendor-proprietary structure, and getting the SMI index and io port and > magic values. Then, you need to know how to setup the registers and > input/output buffers for the call. All of this is already present in > libsmbios.
Perhaps authors of libsmbios could help here?
> Reading nvram is not a valid way to get brighness unless you also do > similar work (parse specific vendor-proprietary SMBIOS structures) to > ensure that you are reading the correct location. This location is > subject to change from BIOS to BIOS and machine to machine. The fact > that you may have observed it in the same location on a few laptops does > not change this fact.
Well, folks reverse-engineering your machines had no idea until now...
> In fact, I have the same objection to the I8K driver in the kernel. It > has hardcoded SMI calls, that are subject to change. There is a proper > way to get the correct IO ports to make this safe, but it is not > currently being done.
Could you or someone at Dell submit patches to correct this? -- 64 bytes from 195.113.31.123: icmp_seq=28 ttl=51 time=448769.1 ms
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