From a839136ca47f79dcdb403cd7a0c5f4798466ac48 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Jos=C3=A9=20Roberto=20de=20Souza?= Date: Thu, 26 Sep 2019 14:06:58 -0700 Subject: [PATCH] drm/i915/tgl: Fix dkl link training MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Link training is failling when running link at 2.7GHz and 1.62GHz and following BSpec pll algorithm. Comparing the values calculated and the ones from the reference table it looks like MG_CLKTOP2_CORECLKCTL1_A_DIVRATIO should not always set to 5. For DP ports ICL mg pll algorithm sets it to 10 or 5 based on div2 value, that matches with dkl hardcoded table. So implementing this way as it proved to work in HW and leaving a comment so we know why it do not match BSpec. v4: Using the same is_dp check as ICL, need testing on HDMI over tc port Issue reported on BSpec 49204. Reviewed-by: Imre Deak Signed-off-by: José Roberto de Souza Link: https://patchwork.freedesktop.org/patch/msgid/20190926210659.56317-3-jose.souza@intel.com --- drivers/gpu/drm/i915/display/intel_dpll_mgr.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_dpll_mgr.c b/drivers/gpu/drm/i915/display/intel_dpll_mgr.c index 69abafa45ce9..be69a2344294 100644 --- a/drivers/gpu/drm/i915/display/intel_dpll_mgr.c +++ b/drivers/gpu/drm/i915/display/intel_dpll_mgr.c @@ -2630,13 +2630,13 @@ static bool icl_mg_pll_find_divisors(int clock_khz, bool is_dp, bool use_ssc, continue; if (div2 >= 2) { - if (is_dkl) { - a_divratio = 5; - tlinedrv = 1; - } else { - a_divratio = is_dp ? 10 : 5; - tlinedrv = 2; - } + /* + * Note: a_divratio not matching TGL BSpec + * algorithm but matching hardcoded values and + * working on HW for DP alt-mode at least + */ + a_divratio = is_dp ? 10 : 5; + tlinedrv = is_dkl ? 1 : 2; } else { a_divratio = 5; tlinedrv = 0; -- 2.45.2