args->flags & ~(I915_MMAP_WC) 7ec9f8e589bca0a Linux scatterlist API
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))
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;
#2 Updated by ftigeot about 3 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.