Bug #2903

args->flags & ~(I915_MMAP_WC) 7ec9f8e589bca0a Linux scatterlist API

Added by davshao over 4 years ago. Updated over 4 years ago.

Target version:
Start date:
Due date:
% Done:


Estimated time:


Commit 7ec9f8e589bca0a drm/i915/gem: Switch to the Linux scatterlist API
does a bit more than that. Commenting out the newly added

if (args->flags & ~(I915_MMAP_WC))
return -EINVAL;

in i915_gem.c allows an Asrock Z77M motherboard machine using current pkgsrc with dports patches backported to once again startx xfce4.

Given that using packages from dports on the same machine allows startx xfce4, it would appear the fault is mine for using a hacked version of pkgsrc; nonetheless, I don't have the slightest idea what to do in userspace to avoid the conflict with the newly added check.

As an aside, I don't understand the logic of the following code in i915_gem_gtt.c, so in the attached diff the addition is commented out as well:

ppgtt->base.allocate_va_range = aliasing ? NULL : gen6_alloc_va_range;
ppgtt->base.allocate_va_range = gen6_alloc_va_range;


scatter.diff (1.19 KB) scatter.diff davshao, 04/24/2016 12:25 AM
dmesg_asrock_20160423.txt (115 KB) dmesg_asrock_20160423.txt davshao, 04/24/2016 12:26 AM



Updated by davshao over 4 years ago

Here is the dmesg from the affected machine.


Updated by ftigeot over 4 years ago

The I915_MMAP_WC change was indeed not strictly related to the switch to the scatterlist API but is part of the Linux 4.2 drm/i915 driver.
Since we aim to keep this driver as close to upstream Linux as possible, I'd very much like to keep this couple of lines.

At first glance, your pkgsrc versions of libdrm and/or xf86-video-intel could be too old to properly handle the Linux 4.2 kernel driver.


Updated by ftigeot over 4 years ago

Having two ppgtt->base.allocate_va_range double assignment in i915_gem_gtt.c was indeed an error and a fix has been pushed to master.
Thanks for noticing it!


Updated by ftigeot over 4 years ago

  • Status changed from New to Closed

Also available in: Atom PDF