From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lelvem-ot01.ext.ti.com (lelvem-ot01.ext.ti.com [198.47.23.234]) (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 BAC50635 for ; Thu, 17 Jul 2025 09:37:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.47.23.234 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752745072; cv=none; b=aiZ6dcsBUsENTUaY5uIGSrS0BGUPVuAlMCv1N8Do8eN/rl+qIUnw7cZt9Pm8Gy6vpjuUpQ1AogDH9U+40kbHm53F0AR5E34JYohhaaMDokDqVL4SOMZFhlWNdamAWIl6vyQ/t0u8bW2GRTl7yxsx4S+orAbRw/lD/X6VjgrzjkU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752745072; c=relaxed/simple; bh=GbK2yVCCDDiG6f9NqPxCDdSWHw8yuMPwK1X0I1wo5Sc=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=JQ03TVyX5yLxspfRh+1zeBznmWy4LM2wUsOl25WySxKs3x+OHUaLQ2b8Bhwf4dlGeLSklVTGM6rVH1edUfW4rl3ZTWbKJmBYrpmpMKLPi6TMJoBBHxktWVtEMrlWxKREHoG5TP4Xonq+VUv9xzljlbYXrlSUz5v2ZR07YATM7iU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=ti.com; spf=pass smtp.mailfrom=ti.com; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b=bqWLdI83; arc=none smtp.client-ip=198.47.23.234 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=ti.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ti.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="bqWLdI83" Received: from lelvem-sh02.itg.ti.com ([10.180.78.226]) by lelvem-ot01.ext.ti.com (8.15.2/8.15.2) with ESMTP id 56H9b60e2705714; Thu, 17 Jul 2025 04:37:06 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1752745026; bh=grVloWar2O621fo+lHDBYQS6zJaquwGGstUgJpQKtxI=; h=Date:Subject:To:CC:References:From:In-Reply-To; b=bqWLdI83FpU0lpfxPEaArnuH/G6gIqCUioxaySxEYehblTjj1rEGffjtNwJhNDC7x GIGPl4rGSOjYyF4bWbpIai6ox4QPEhcWgWDjeceje+nkyXfR7ddQB6M6jipgM7OcoW IaK4tvBOmfm1d4DyTRiUjKIlH6ujF0GWx2n1Hg/A= Received: from DLEE103.ent.ti.com (dlee103.ent.ti.com [157.170.170.33]) by lelvem-sh02.itg.ti.com (8.18.1/8.18.1) with ESMTPS id 56H9b5Io2698835 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA256 bits=128 verify=FAIL); Thu, 17 Jul 2025 04:37:05 -0500 Received: from DLEE101.ent.ti.com (157.170.170.31) by DLEE103.ent.ti.com (157.170.170.33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.55; Thu, 17 Jul 2025 04:37:05 -0500 Received: from lelvem-mr05.itg.ti.com (10.180.75.9) by DLEE101.ent.ti.com (157.170.170.31) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.55 via Frontend Transport; Thu, 17 Jul 2025 04:37:05 -0500 Received: from [172.24.227.193] (devarsh-precision-tower-3620.dhcp.ti.com [172.24.227.193]) by lelvem-mr05.itg.ti.com (8.18.1/8.18.1) with ESMTP id 56H9awA31949552; Thu, 17 Jul 2025 04:36:59 -0500 Message-ID: <8728de80-f154-46fa-a8a6-da40cb5fdc65@ti.com> Date: Thu, 17 Jul 2025 15:06:58 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 17/17] drm/bridge: cdns-dsi: Don't fail on MIPI_DSI_MODE_VIDEO_BURST To: Tomi Valkeinen , Jyri Sarha , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Vinod Koul , Kishon Vijay Abraham I , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Jayesh Choudhary , Dmitry Baryshkov CC: , , , Francesco Dolcini , Aradhya Bhatia , Parth Pancholi References: <20250618-cdns-dsi-impro-v4-0-862c841dbe02@ideasonboard.com> <20250618-cdns-dsi-impro-v4-17-862c841dbe02@ideasonboard.com> Content-Language: en-US From: Devarsh Thakkar In-Reply-To: <20250618-cdns-dsi-impro-v4-17-862c841dbe02@ideasonboard.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-C2ProcessedOrg: 333ef613-75bf-4e12-a4b1-8e3623f5dcea Hi Tomi Thanks for the patch. On 18/06/25 15:29, Tomi Valkeinen wrote: > While the cdns-dsi does not support DSI burst mode, the burst mode is > essentially DSI event mode with more versatile clocking and timings. I don't fully agree with this statement, DSI burst mode and DSI event mode are two different things having separate requirements. DSI burst mode maps to MIPI_DSI_MODE_VIDEO_BURST. I don't see a separate flag for event mode but I guess, > Thus cdns-dsi doesn't need to fail if the DSI peripheral driver requests > MIPI_DSI_MODE_VIDEO_BURST. MIPI_DSI_MODE_VIDEO_BURST is currently not supported by the cadence DSI host driver, so only if DSI peripheral driver is saying that burst mode is the only one it supports in that case only we should fail. > > In my particular use case, this allows the use of ti-sn65dsi83 driver. > > Tested-by: Parth Pancholi > Tested-by: Jayesh Choudhary > Signed-off-by: Tomi Valkeinen > --- > drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c > index 114d883c65dc..09b289f0fcbf 100644 > --- a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c > +++ b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c > @@ -1052,10 +1052,6 @@ static int cdns_dsi_attach(struct mipi_dsi_host *host, > if (output->dev) > return -EBUSY; > > - /* We do not support burst mode yet. */ > - if (dev->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) > - return -ENOTSUPP; > - Removing this check also gives a false impression that burst mode is supported by the driver and can also lead to failures too in case device is only supporting burst mode. I think it makes sense to fail only if burst mode is the only one being supported by the device, something like below should work I believe, if (dev->mode_flags & MIPI_DSI_MODE_VIDEO_BURST == MIPI_DSI_MODE_VIDEO_BURST) return -ENOTSUPP; Regards Devarsh > /* > * The host <-> device link might be described using an OF-graph > * representation, in this case we extract the device of_node from >