[Gentoo] X201 Black Screen Solution

By Tryout |

Friday, October 29, 2010

According to my experiments, while using kernel version between 2.6.32-gentoo-r10 and 2.6.35-gentoo-r9, my Thinkpad X201 always got a black screen, but by applying the following patch, I can boot into framebuffer console with KMS(Kernel ModSetting) on.

1. Under $KERNEL_ROOT/drivers/gpu/drm/i915/intel_display.c
2. 858 intel_g4x_find_best_PLL(const intel_limit_t *limit, struct drm_crtc *crtc,
   859 int target, int refclk, intel_clock_t *best_clock)
   860 {
   861 struct drm_device *dev = crtc->dev;
   862 struct drm_i915_private *dev_priv = dev->dev_private;
   863 intel_clock_t clock;
   864 int max_n;
   865 bool found;
   866 /* approximately equals target * 0.00585 */
   867 int err_most = (target >> 8) + (target >> 9)
   868 // patch for KMS black screen
   869 err_most += 50;
   

   870 found = false;

But now, this bug/issue seems to be fixed in kernel version 2.6.36, I just emerge the gentoo-sources-2.6.36 without applying above patch, and it works.

Keywords: ThinkPad, X201, Gentoo, Black Screen, KMS