From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C449D11C88 for ; Mon, 12 Jun 2023 10:40:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4E8B0C433D2; Mon, 12 Jun 2023 10:40:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1686566408; bh=LApKEcfwhkqcV7ae3DW8lqG2TCM3cSTXtI/x7nc4l7o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qUgL6cIduQKlPIqx7y3W2XDhEHXEGZ3F1ArLRRLrrVkZrtnD3Rd+zacScbvrGq9LN OLc73RoUfGaYfJxWS+Mg0ZO+M9nMz2BO+Uzxzzw3h9geAX0DWFAKsWu51kCX/YAE2n sYC2xYnXRlYgaHq3JQikPVnTi5CpnwyL5CYaOV9Y= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Jouni=20H=C3=B6gander?= , =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= , Sasha Levin Subject: [PATCH 6.1 020/132] drm/i915: Explain the magic numbers for AUX SYNC/precharge length Date: Mon, 12 Jun 2023 12:25:54 +0200 Message-ID: <20230612101711.166750526@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230612101710.279705932@linuxfoundation.org> References: <20230612101710.279705932@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Ville Syrjälä [ Upstream commit 26bfc3f36f2104c174dfc72415547d5c28ef3f1c ] Replace the hardcoded final numbers in the AUX SYNC/precharge setup, and derive those from numbers from the (e)DP specs. The new functions can serve as the single point of truth for the number of SYNC pulses we use. Cc: Jouni Högander Signed-off-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20230329172434.18744-2-ville.syrjala@linux.intel.com Reviewed-by: Jouni Högander Stable-dep-of: 2d6f2f79e065 ("drm/i915: Use 18 fast wake AUX sync len") Signed-off-by: Sasha Levin --- drivers/gpu/drm/i915/display/intel_dp_aux.c | 32 +++++++++++++++++++-- 1 file changed, 29 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux.c b/drivers/gpu/drm/i915/display/intel_dp_aux.c index 7f3f2d50e6cde..8325868770994 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_aux.c +++ b/drivers/gpu/drm/i915/display/intel_dp_aux.c @@ -119,6 +119,32 @@ static u32 skl_get_aux_clock_divider(struct intel_dp *intel_dp, int index) return index ? 0 : 1; } +static int intel_dp_aux_sync_len(void) +{ + int precharge = 16; /* 10-16 */ + int preamble = 16; + + return precharge + preamble; +} + +static int intel_dp_aux_fw_sync_len(void) +{ + int precharge = 16; /* 10-16 */ + int preamble = 8; + + return precharge + preamble; +} + +static int g4x_dp_aux_precharge_len(void) +{ + int precharge_min = 10; + int preamble = 16; + + /* HW wants the length of the extra precharge in 2us units */ + return (intel_dp_aux_sync_len() - + precharge_min - preamble) / 2; +} + static u32 g4x_get_aux_send_ctl(struct intel_dp *intel_dp, int send_bytes, u32 aux_clock_divider) @@ -141,7 +167,7 @@ static u32 g4x_get_aux_send_ctl(struct intel_dp *intel_dp, timeout | DP_AUX_CH_CTL_RECEIVE_ERROR | (send_bytes << DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT) | - (3 << DP_AUX_CH_CTL_PRECHARGE_2US_SHIFT) | + (g4x_dp_aux_precharge_len() << DP_AUX_CH_CTL_PRECHARGE_2US_SHIFT) | (aux_clock_divider << DP_AUX_CH_CTL_BIT_CLOCK_2X_SHIFT); } @@ -165,8 +191,8 @@ static u32 skl_get_aux_send_ctl(struct intel_dp *intel_dp, DP_AUX_CH_CTL_TIME_OUT_MAX | DP_AUX_CH_CTL_RECEIVE_ERROR | (send_bytes << DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT) | - DP_AUX_CH_CTL_FW_SYNC_PULSE_SKL(24) | - DP_AUX_CH_CTL_SYNC_PULSE_SKL(32); + DP_AUX_CH_CTL_FW_SYNC_PULSE_SKL(intel_dp_aux_fw_sync_len()) | + DP_AUX_CH_CTL_SYNC_PULSE_SKL(intel_dp_aux_sync_len()); if (intel_tc_port_in_tbt_alt_mode(dig_port)) ret |= DP_AUX_CH_CTL_TBT_IO; -- 2.39.2