drm/i915: Allow fuzzy matching in intel_compare_link_m_n
This prevents a unnecessary modeset on a dell XPS 13 (2016).
N is always a power of 2, which means that for fuzzy matching we should
compare for inequality on the n values, then do fuzzy matching on the m
values.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Tested-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/568D0E93.304@linux.intel.com
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 043adfa..ab0b406 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -12577,19 +12577,22 @@
BUILD_BUG_ON(DATA_LINK_M_N_MASK > INT_MAX);
- if (m > m2) {
- while (m > m2) {
+ if (n > n2) {
+ while (n > n2) {
m2 <<= 1;
n2 <<= 1;
}
- } else if (m < m2) {
- while (m < m2) {
+ } else if (n < n2) {
+ while (n < n2) {
m <<= 1;
n <<= 1;
}
}
- return m == m2 && n == n2;
+ if (n != n2)
+ return false;
+
+ return intel_fuzzy_clock_check(m, m2);
}
static bool