Re: x250 inteldrm freeze on 4:3 external monitor

[Paul Irofti]

> >Fix:
>       Unknown.

Here is a potential fix.


Index: dev/pci/drm/i915/i915_drv.h
===================================================================
RCS file: /cvs/src/sys/dev/pci/drm/i915/i915_drv.h,v
retrieving revision 1.77
diff -u -p -u -p -r1.77 i915_drv.h
--- dev/pci/drm/i915/i915_drv.h 19 Jul 2017 22:05:58 -0000      1.77
+++ dev/pci/drm/i915/i915_drv.h 20 Jul 2017 12:46:16 -0000
@@ -3692,7 +3692,8 @@ wait_remaining_ms_from_jiffies(unsigned 
 static inline void
 wait_remaining_ms_from_jiffies(unsigned long timestamp_jiffies, int to_wait_ms)
 {
-       unsigned long target_jiffies, tmp_jiffies, remaining_jiffies;
+       unsigned long target_jiffies, tmp_jiffies;
+       long remaining_jiffies;
 
        if (cold) {
                delay(to_wait_ms * 1000);
@@ -3709,7 +3710,8 @@ wait_remaining_ms_from_jiffies(unsigned 
 
        while (time_after(target_jiffies, tmp_jiffies)) {
                remaining_jiffies = target_jiffies - tmp_jiffies;
-               tsleep(&tmp_jiffies, PWAIT, "wrmfj", remaining_jiffies);
+               if (remaining_jiffies)
+                       tsleep(&tmp_jiffies, PWAIT, "wrmfj", remaining_jiffies);
                tmp_jiffies = jiffies;
        }
 }