The N value was computed by kernel driver that based on synchronous clock
mode. But only specific N value (0x8000) would be acceptable for
LG LP140WF6-SPM1 eDP panel which is running at asynchronous clock mode.
With the other N value, Tcon will enter BITS mode and display black screen.
Add this panel into quirk database and give particular N value when
calculate M/N divider.
v2:
- Use CONSTANT_N instead of LIMITED_M_N and set N as 0x8000 for particular
branch/sink device.
- Fix typo.
Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
Cc: Cooper Chiou <cooper.chiou@xxxxxxxxx>
Cc: Matt Atwood <matthew.s.atwood@xxxxxxxxx>
Signed-off-by: Lee, Shawn C <shawn.c.lee@xxxxxxxxx>
---
drivers/gpu/drm/drm_dp_helper.c | 14 +++++++++++++-
drivers/gpu/drm/i915/intel_display.c | 25 ++++++++-----------------
drivers/gpu/drm/i915/intel_display.h | 2 +-
drivers/gpu/drm/i915/intel_dp.c | 8 ++++----
drivers/gpu/drm/i915/intel_dp_mst.c | 6 +++---
include/drm/drm_dp_helper.h | 6 +++---
6 files changed, 32 insertions(+), 29 deletions(-)
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index 0cccbcb2d03e..eb9d97456db1 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -1256,18 +1256,27 @@ EXPORT_SYMBOL(drm_dp_stop_crc);
struct dpcd_quirk {
u8 oui[3];
+ u8 device_id[6];
bool is_branch;
u32 quirks;
};
#define OUI(first, second, third) { (first), (second), (third) }
+#define DEVICE_ID(first, second, third, fourth, fifth, sixth) \
+ { (first), (second), (third), (fourth), (fifth), (sixth) }
+
+#define DEVICE_ID_ANY DEVICE_ID(0, 0, 0, 0, 0, 0)
static const struct dpcd_quirk dpcd_quirk_list[] = {
/* Analogix 7737 needs reduced M and N at HBR2 link rates */
- { OUI(0x00, 0x22, 0xb9), true, BIT(DP_DPCD_QUIRK_LIMITED_M_N) },
+ { OUI(0x00, 0x22, 0xb9), DEVICE_ID_ANY, true, BIT(DP_DPCD_QUIRK_CONSTANT_N) },
+ /* LG LP140WF6-SPM1 eDP panel */
+ { OUI(0x00, 0x22, 0xb9), DEVICE_ID('s', 'i', 'v', 'a', 'r', 'T'), false, BIT(DP_DPCD_QUIRK_CONSTANT_N) },
};
#undef OUI
+#undef DEVICE_ID
+#undef DEVICE_ID_ANY
/*
* Get a bit mask of DPCD quirks for the sink/branch device identified by
@@ -1293,6 +1302,9 @@ drm_dp_get_quirks(const struct drm_dp_dpcd_ident *ident, bool is_branch)
if (memcmp(quirk->oui, ident->oui, sizeof(ident->oui)) != 0)
continue;
+ if (!is_branch && memcmp(quirk->device_id, ident->device_id, 6) != 0)
+ continue;
+
quirks |= quirk->quirks;
}
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index ec3e24f07486..268b1f546b77 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6680,22 +6680,13 @@ 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.
- */
- 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);
}
@@ -6704,18 +6695,18 @@ 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 43f080c6538d..8e8bd5eed2c2 100644
--- a/drivers/gpu/drm/i915/intel_display.h
+++ b/drivers/gpu/drm/i915/intel_display.h
@@ -379,7 +379,7 @@ 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);
bool is_ccs_modifier(u64 modifier);
#endif
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 436c22de33b6..6b4c19123f2a 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1998,8 +1998,8 @@ 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;
@@ -2064,7 +2064,7 @@ 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) {
@@ -2074,7 +2074,7 @@ 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 352e5216cc65..184023435b08 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;
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 05cc31b5db16..ab0914ef5e38 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -1260,12 +1260,12 @@ int drm_dp_read_desc(struct drm_dp_aux *aux, struct drm_dp_desc *desc,
*/
enum drm_dp_quirk {
/**
- * @DP_DPCD_QUIRK_LIMITED_M_N:
+ * @DP_DPCD_QUIRK_CONSTANT_N:
*
* The device requires main link attributes Mvid and Nvid to be limited
- * to 16 bits.
+ * to 16 bits.So will give a constant value (0x8000) for compatability.
*/
- DP_DPCD_QUIRK_LIMITED_M_N,
+ DP_DPCD_QUIRK_CONSTANT_N,
};
/**
--
2.7.4
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