From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=marek.ca header.i=@marek.ca header.b="YKnoJTwW" Received: from mail-qt1-x82b.google.com (mail-qt1-x82b.google.com [IPv6:2607:f8b0:4864:20::82b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C6E66D4A for ; Thu, 16 Nov 2023 10:46:45 -0800 (PST) Received: by mail-qt1-x82b.google.com with SMTP id d75a77b69052e-41b7fd8f458so6443911cf.0 for ; Thu, 16 Nov 2023 10:46:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=marek.ca; s=google; t=1700160405; x=1700765205; darn=vger.kernel.org; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:from:references:cc:to:subject:from:to:cc :subject:date:message-id:reply-to; bh=If/44f1KPyVE2d2iqlt11gTcl1EXO2kaaJZBfwh5YxI=; b=YKnoJTwWuoErDwGyNtj03dwhKkhdBux3KS6L8wRcNoDxWyMYs7u/4uOC2SkaFliGVB 9azwrgMmXVc6DnUfOVYn1nUuM2HiB5B0f7ioZloLqc5f9hLPrhZ8EbULvoou5bE9UCvQ c3M3d5gBZL72swIsGsEUxfsyQhmIKQY6yJKjCdkN8a/Ziss2Nkfe3Hg7e+zuUGjwMZEM yZhRGFE1Cxex8vvYi0+l23UcyC4R/NtObdKkKtjH3NmC9Loj7ILIQj7OjagCvkqSZcRc OHdS10Of/jcECJGmzQpazM4bHDPERKgCfsYj5+hEHoziVgJcscSel598xwSWF+qkqXVa 7Bjw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1700160405; x=1700765205; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:from:references:cc:to:subject :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=If/44f1KPyVE2d2iqlt11gTcl1EXO2kaaJZBfwh5YxI=; b=d6Zog9q7qXIxbkSHFCYSbB9/9odPMRwEDK4/yBLqweowHDfJYwYxBRiVNThl5IkodG aXhTUb9Tbf2ErD5XxLzZ6LrEmBirQrISBJWQk5q56X9DgNHjMi8lsS0XDbBpYnCEz4rE Ea+z3BKVulOaOYovAQ1Nb8aPpSXWmBvgFkGjR6zxaDdVb5MnR3Wc5WScl5fS6u7hBqRb wwj5qGFymX5ik9UgdNkOQ5jUvoHEav4NUoLacJRS79CfjwuITZ60R/Yo/4Q2fEehl63U /19KthFXSYMxcPEqS/NBjtyVkRlFS62Tp8fImglHfQo2v6WOZ0iBg6hZodgsL2CCcP2U cUhg== X-Gm-Message-State: AOJu0YykobZStL8aHMh7kVLYyp35+LkVjeKu/siRbCoyxH7naGPl5u/5 1rpUo9COpfhgzKp7Q+5B/5K2hA== X-Google-Smtp-Source: AGHT+IFQlwjNqtRd3lxS5p0T5Vg8UQ+JyMTZejmIFz8gVnKZabprGWmddPa0pf0JYS0omO1Kk+ALrQ== X-Received: by 2002:ac8:7f14:0:b0:419:6954:3ba2 with SMTP id f20-20020ac87f14000000b0041969543ba2mr11124161qtk.43.1700160404914; Thu, 16 Nov 2023 10:46:44 -0800 (PST) Received: from [192.168.0.189] (modemcable125.110-19-135.mc.videotron.ca. [135.19.110.125]) by smtp.gmail.com with ESMTPSA id w19-20020ac843d3000000b0041991642c62sm4493571qtn.73.2023.11.16.10.46.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 16 Nov 2023 10:46:44 -0800 (PST) Subject: Re: [PATCH v2 4/6] drm/msm/dsi: add a comment to explain pkt_per_line encoding To: Dmitry Baryshkov Cc: freedreno@lists.freedesktop.org, Rob Clark , Abhinav Kumar , Sean Paul , Marijn Suijten , David Airlie , Daniel Vetter , Jessica Zhang , Konrad Dybcio , Jiasheng Jiang , "open list:DRM DRIVER FOR MSM ADRENO GPU" , "open list:DRM DRIVER FOR MSM ADRENO GPU" , open list References: <20231114225857.19702-1-jonathan@marek.ca> <20231114225857.19702-5-jonathan@marek.ca> From: Jonathan Marek Message-ID: Date: Thu, 16 Nov 2023 13:45:47 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit On 11/15/23 2:38 AM, Dmitry Baryshkov wrote: > On Wed, 15 Nov 2023 at 01:00, Jonathan Marek wrote: >> >> Make it clear why the pkt_per_line value is being "divided by 2". >> >> Signed-off-by: Jonathan Marek >> --- >> drivers/gpu/drm/msm/dsi/dsi_host.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c >> index 66f198e21a7e..842765063b1b 100644 >> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c >> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c >> @@ -877,6 +877,8 @@ static void dsi_update_dsc_timing(struct msm_dsi_host *msm_host, bool is_cmd_mod >> /* DSI_VIDEO_COMPRESSION_MODE & DSI_COMMAND_COMPRESSION_MODE >> * registers have similar offsets, so for below common code use >> * DSI_VIDEO_COMPRESSION_MODE_XXXX for setting bits >> + * >> + * pkt_per_line is log2 encoded, >>1 works for supported values (1,2,4) >> */ >> reg |= DSI_VIDEO_COMPRESSION_MODE_CTRL_PKT_PER_LINE(pkt_per_line >> 1); > > Should we switch to ffs() or fls() instead? > Just a ffs() on its own can be confusing as well (without the information that only powers of two are possible), I think like this is better. >> reg |= DSI_VIDEO_COMPRESSION_MODE_CTRL_EOL_BYTE_NUM(eol_byte_num); >> -- >> 2.26.1 >> > >