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-rw-r--r--drivers/gpu/drm/i915/intel_display.c28
-rw-r--r--drivers/gpu/drm/i915/intel_display.h2
-rw-r--r--drivers/gpu/drm/i915/intel_dp.c8
-rw-r--r--drivers/gpu/drm/i915/intel_dp_mst.c6
4 files changed, 21 insertions, 23 deletions
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index c24bc848ac6c..611b425b50f1 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6677,22 +6677,20 @@ intel_reduce_m_n_ratio(uint32_t *num, uint32_t *den)
static void compute_m_n(unsigned int m, unsigned int n,
uint32_t *ret_m, uint32_t *ret_n,
- bool reduce_m_n)
+ bool constant_n)
{
/*
- * Reduce M/N as much as possible without loss in precision. Several DP
- * dongles in particular seem to be fussy about too large *link* M/N
- * values. The passed in values are more likely to have the least
- * significant bits zero than M after rounding below, so do this first.
+ * Several DP dongles in particular seem to be fussy about
+ * too large link M/N values. Give N value as 0x8000 that
+ * should be acceptable by specific devices. 0x8000 is the
+ * specified fixed N value for asynchronous clock mode,
+ * which the devices expect also in synchronous clock mode.
*/
- if (reduce_m_n) {
- while ((m & 1) == 0 && (n & 1) == 0) {
- m >>= 1;
- n >>= 1;
- }
- }
+ if (constant_n)
+ *ret_n = 0x8000;
+ else
+ *ret_n = min_t(unsigned int, roundup_pow_of_two(n), DATA_LINK_N_MAX);
- *ret_n = min_t(unsigned int, roundup_pow_of_two(n), DATA_LINK_N_MAX);
*ret_m = div_u64((uint64_t) m * *ret_n, n);
intel_reduce_m_n_ratio(ret_m, ret_n);
}
@@ -6701,18 +6699,18 @@ void
intel_link_compute_m_n(int bits_per_pixel, int nlanes,
int pixel_clock, int link_clock,
struct intel_link_m_n *m_n,
- bool reduce_m_n)
+ bool constant_n)
{
m_n->tu = 64;
compute_m_n(bits_per_pixel * pixel_clock,
link_clock * nlanes * 8,
&m_n->gmch_m, &m_n->gmch_n,
- reduce_m_n);
+ constant_n);
compute_m_n(pixel_clock, link_clock,
&m_n->link_m, &m_n->link_n,
- reduce_m_n);
+ constant_n);
}
static inline bool intel_panel_use_ssc(struct drm_i915_private *dev_priv)
diff --git a/drivers/gpu/drm/i915/intel_display.h b/drivers/gpu/drm/i915/intel_display.h
index 809c06ae4c07..58ba614862e5 100644
--- a/drivers/gpu/drm/i915/intel_display.h
+++ b/drivers/gpu/drm/i915/intel_display.h
@@ -382,6 +382,6 @@ struct intel_link_m_n {
void intel_link_compute_m_n(int bpp, int nlanes,
int pixel_clock, int link_clock,
struct intel_link_m_n *m_n,
- bool reduce_m_n);
+ bool constant_n);
#endif
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index cd0f649b57a5..29212d317f58 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1834,8 +1834,8 @@ intel_dp_compute_config(struct intel_encoder *encoder,
struct intel_connector *intel_connector = intel_dp->attached_connector;
struct intel_digital_connector_state *intel_conn_state =
to_intel_digital_connector_state(conn_state);
- bool reduce_m_n = drm_dp_has_quirk(&intel_dp->desc,
- DP_DPCD_QUIRK_LIMITED_M_N);
+ bool constant_n = drm_dp_has_quirk(&intel_dp->desc,
+ DP_DPCD_QUIRK_CONSTANT_N);
if (HAS_PCH_SPLIT(dev_priv) && !HAS_DDI(dev_priv) && port != PORT_A)
pipe_config->has_pch_encoder = true;
@@ -1900,7 +1900,7 @@ intel_dp_compute_config(struct intel_encoder *encoder,
adjusted_mode->crtc_clock,
pipe_config->port_clock,
&pipe_config->dp_m_n,
- reduce_m_n);
+ constant_n);
if (intel_connector->panel.downclock_mode != NULL &&
dev_priv->drrs.type == SEAMLESS_DRRS_SUPPORT) {
@@ -1910,7 +1910,7 @@ intel_dp_compute_config(struct intel_encoder *encoder,
intel_connector->panel.downclock_mode->clock,
pipe_config->port_clock,
&pipe_config->dp_m2_n2,
- reduce_m_n);
+ constant_n);
}
if (!HAS_DDI(dev_priv))
diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
index 7e3e01607643..b7505879b1f7 100644
--- a/drivers/gpu/drm/i915/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/intel_dp_mst.c
@@ -45,8 +45,8 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
int lane_count, slots;
const struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
int mst_pbn;
- bool reduce_m_n = drm_dp_has_quirk(&intel_dp->desc,
- DP_DPCD_QUIRK_LIMITED_M_N);
+ bool constant_n = drm_dp_has_quirk(&intel_dp->desc,
+ DP_DPCD_QUIRK_CONSTANT_N);
if (adjusted_mode->flags & DRM_MODE_FLAG_DBLSCAN)
return false;
@@ -87,7 +87,7 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
adjusted_mode->crtc_clock,
pipe_config->port_clock,
&pipe_config->dp_m_n,
- reduce_m_n);
+ constant_n);
pipe_config->dp_m_n.tu = slots;