Messages in this thread | | | Date | Tue, 7 Apr 2015 09:46:26 -0500 | From | Aravind Gopalakrishnan <> | Subject | Re: [PATCH] x86, aperture: Check for GART before accessing GART registers |
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On 4/7/2015 7:34 AM, Borislav Petkov wrote: > On Mon, Apr 06, 2015 at 06:10:22PM -0500, Aravind Gopalakrishnan wrote: >>> So what happens if !early_pci_allowed() but the GART is present? We'll >>> set amd_northbridges.flags |= AMD_NB_GART, but won't run any of the >>> setup code in aperture_64.c, right? Is that a valid setup? >> It might be a valid setup. But it would work correctly only if BIOS did the >> right thing with setting up aperture space. >> >> If !early_pci_allowed() and BIOS did not setup aperture correctly, that >> would have caused problems already. >> But it has not been an issue so far right? > I think the right question to ask is: > > What are we doing when there's no GART? > > So what you probably want to do is: > > if (!amd_gart_present()) > return -ENODEV; > > *before* the compound check. > > Now, if we have detected a GART, i.e., amd_gart_present() is TRUE, the > code will behave as it used to behave before. > > This should be the least intrusive change going forward IMHO. >
Okay. I'll do that and correct the typos Ingo pointed out earlier and resend.
Thanks, -Aravind.
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