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Dell D820, SSD support


dutchcow

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There seems to be more code in the BIOS one.

 

@Bronxteck

That won't work until OSX can access TRIM and NCQ without AHCI enabled, Windows can do it. Linux has a bootflag to switch the controller in to AHCI mode. It's just OSX unfortunatly. There is no new firmware for my drive. I'm using a V300 Kingston in the D820, there are no updates yet. It has build in garbage collection, so TRIM is not really my first worry. The lack of NCQ and having the controller in legacy mode is what's costing speed, a lot of it.

 

Ideally Dell would release a new BIOS with a switch for AHCI mode. But even on a lot of ICH8-M notebooks the option is nowhere to be found. This fix applies to that chipset too.

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There seems to be more code in the BIOS one.

[...]

'afraid not, the tables are 99.999% identical. Only line 5540 bears a tiny difference (unrelated to SATA controller) :

Method (ZEJ0, 1, NotSerialized) -> in BIOS table

Method (_EJ0, 1, NotSerialized) -> in Linux table

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If DSDT patching does not appear feasible, I was thinking that maybe a Chameleon module could work (where the device id would be changed from 27c4 to 27c5) -> that would in theory patch the kernel and be similar to those patches you see on Linux. Something to suggest to Chameleon developpers possibly... Wouldn't that operate before the OS begins to load?

 

Isn't the Cham Sata module doing something similar?

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If anything it has to be done from the RAM or something. I can toggle the interface in the grub menu, but I can't boot in to the OS. However if I make the changes from a USB grub install the system doesn't crash but I'm unable to access any drives (I think this has to do with memory space/mapping but is far above my level). The best method would be via BIOS/DSDT and if that fails some other way like you said with a module that gets loaded into the RAM before boot. I also have no idea if my disk names stay the same when switch mode. On my D630 switching AHCI on or off still makes OSX boot fine. So I don't think that should be a problem.

 

If only I can find the old free version of DIY ViDOck bootdisk. I know that can change pci registers and then use grub4dos to chainload into anything. But I'm not willing to pay to test it, there will be no refund if it doesn't work on my system. If anyone has an old version laying around let me know so I can test it.

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Well after long a rigerous testing with EMlyDinEsH it is possible to enable AHCI with a DSDT patch, but not in OSX. I'm too clueless to explain the details, but I think OSX is somehow blocking it. Maybe EMlyDinEsH can explain some details here.

 

For anyone who still wants to get this to work you should look into chainloading into chameleon via grub/grub4dos and use grub or dos commands to set the pci stuff and then boot OSX. However I havent gotten this to work, when I do I will share the image here. It will be Linux or Freedos based.

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