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I've got a Dell Inspiron 15R 7520 with AMD's hybrid "PowerXpress" graphics. The integrated graphics card is (if I understand it correctly) integrated with the i7-3612QM processor, and the discrete graphics card is a "Southern Islands" Radeon HD 7730M. The integrated graphics work perfectly under Arch.

However, the discrete graphics don't. I have tried several different methods, and the one that seems to get me the farthest with the least effort is the AUR package catalyst-total-pxp. After installing, rebooting, and issuing the commands

# aticonfig --initial
# pxp_switch_catalyst amd
# X

X completely fails to start. The X log can be found here. I don't understand what is failing; potentially, it has something to do with the way my card is hooked up--I think it's muxless, but I really don't know. What is the matter here? How can I get hybrid graphics working on Arch? Any help would be appreciated.

Note: the pxp_switch_catalyst command is just a script that moves special Xorg config files into place, switches libGL to the discrete version, etc. If you download the tarball from the AUR link, you can read the script.

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Have you added the fglrx module in /etc/modules-load.d/ ? You also need to disable KMS. –  user174577 Dec 12 '12 at 23:26
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3 Answers

It seems that this laptop uses muxless graphics--a similar scheme to Nvidia's Optimus technology. In fact, the Bumblebee project (which was created to bring Optimus support to Linux) has been shown to work at least basically with AMD's setup, because it's basically the same setup, just with a different card and thus different drivers.

However, with my particular setup, there are a couple things holding Bumblebee back: namely, drivers. The free drivers aren't up to snuff yet for the 77xx series cards and are therefore useless with Bumblebee. AMD's proprietary drivers don't work because they just plain don't support muxless hybrid graphics--great job, AMD. Hopefully the situation with these drivers will improve, and this card will be usable under Linux.

I gathered most of this information on the relevant Bumblebee Github issue page. If you want more up-to-date information, I suggest scrolling to the bottom of that page and reading up.

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You did try "Auto detect and install" from here, right? ( http://support.amd.com/us/gpudownload/Pages/index.aspx )

Also, I can't seem to find Linux programs, but perhaps you can manage if I just give you the idea. Maybe you'll manage to find a Linux equivalent, or maybe you'll manage to run a Windows program on your Linux system fine, by whatever means. Anyway, those programs are supposed to find the right driver for you, if it exists.

http://alternativeto.net/software/driver-genius/

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Yes, those AMD tools are sadly Windows-only. The Linux tarball doesn't support hybrid graphcis such as mine. (See my answer.) As far as Driver Genius, I'm not sure anything such as that exists for Arch Linux. We instead tend to use the Google and a little bit of reading :). –  thirtythreeforty Jan 8 '13 at 7:28
    
Well, I was thinking that maybe, since Linux users are often, well, professional "tweakers" in a way, and since some people were managing to run a Windows game on Linux through emulation, you might have known of a way to make those Windows tools work for your system, or something. –  Ariane Jan 8 '13 at 7:37
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With the advent of Linux 3.13, the Direct Rendering Infrastructure for Linux and the Direct Rendering Manager for X11 makes AMD's proprietary drivers unneeded--Linux now directly supports dynamic switching between graphics cards! Once PRIME is set up, using the environment variable DRI_PRIME=1 will automatically turn on the discrete card and run the command specified with GL offloaded to the discrete card.

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