drm/i915/glk: Calculate high/low switch count for GLK

As per BSPEC, high/low switch count to be programmed in
terms of byteclock using exit_zero_count and prep_count.
For Geminilake exit/prep counts are already calculated
in terms of byteclock. This patch calculates high/low
switch count using counts value in byteclock, old calculation
leads to screen flicker/shift issue while resuming from S3/S4.

Signed-off-by: Madhav Chauhan <madhav.chauhan@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1494336565-19185-1-git-send-email-madhav.chauhan@intel.com

diff --git a/drivers/gpu/drm/i915/intel_dsi_vbt.c b/drivers/gpu/drm/i915/intel_dsi_vbt.c
index 0dce7792643abb414055fe262de09298e5d485e3..7158c7ce9c0941a05654261e2443bac8b2315b08 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dsi_vbt.c
+++ b/drivers/gpu/drm/i915/intel_dsi_vbt.c
@@ -694,8 +694,8 @@ bool intel_dsi_vbt_init(struct intel_dsi *intel_dsi, u16 panel_id)
                                                clk_zero_cnt << 8 | prepare_cnt;
 
        /*
-        * LP to HS switch count = 4TLPX + PREP_COUNT * 2 + EXIT_ZERO_COUNT * 2
-        *                                      + 10UI + Extra Byte Count
+        * LP to HS switch count = 4TLPX + PREP_COUNT * mul + EXIT_ZERO_COUNT *
+        *                                      mul + 10UI + Extra Byte Count
         *
         * HS to LP switch count = THS-TRAIL + 2TLPX + Extra Byte Count
         * Extra Byte Count is calculated according to number of lanes.
@@ -708,8 +708,8 @@ bool intel_dsi_vbt_init(struct intel_dsi *intel_dsi, u16 panel_id)
        /* B044 */
        /* FIXME:
         * The comment above does not match with the code */
-       lp_to_hs_switch = DIV_ROUND_UP(4 * tlpx_ui + prepare_cnt * 2 +
-                                               exit_zero_cnt * 2 + 10, 8);
+       lp_to_hs_switch = DIV_ROUND_UP(4 * tlpx_ui + prepare_cnt * mul +
+                                               exit_zero_cnt * mul + 10, 8);
 
        hs_to_lp_switch = DIV_ROUND_UP(mipi_config->ths_trail + 2 * tlpx_ui, 8);