From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2B5A7C4321E for ; Fri, 2 Dec 2022 12:22:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233291AbiLBMWK (ORCPT ); Fri, 2 Dec 2022 07:22:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45918 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233501AbiLBMWA (ORCPT ); Fri, 2 Dec 2022 07:22:00 -0500 Received: from phobos.denx.de (phobos.denx.de [IPv6:2a01:238:438b:c500:173d:9f52:ddab:ee01]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B64EFD378C for ; Fri, 2 Dec 2022 04:21:52 -0800 (PST) Received: from [127.0.0.1] (p578adb1c.dip0.t-ipconnect.de [87.138.219.28]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: marex@denx.de) by phobos.denx.de (Postfix) with ESMTPSA id E5CCF84F62; Fri, 2 Dec 2022 13:21:48 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=denx.de; s=phobos-20191101; t=1669983710; bh=DAGUPW1K0fo7i5LI1mBlSSU7CpoTBUXsHq+pagui1DQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=FvfjKoXx+k1LZiSiqRqrx6bAYqdCqJsjUKXcECsFyAt3MVdHtezuJjbgguSjD+fG3 mb5n+/k58PklYuB4tNTJOIhI5dfXqIUpRATUPq/uGrDlZWB5P9W2TpFDiEk7IOEM/l z66Zac9f2KnAlroqrhEBH1Iedw+fMEmpAcLAJIVxIU3V2wE+EyIFcLHpPJktl7Obuk yjhiGAo/DlWvIgkhnmuFzYZi1CLOoALdi27xunKqVX99g4R9x/y2Jk8xcCAgeec0ux 7I0EegmjFdQkpzLlfm1uHOnk9kq/ndI/odUlaBrlQ73nlSyCob7nRzL3F8jaINcJoh 5TfnoUBI5+7Kg== Message-ID: <2ef1aae1-8ff9-22bc-9817-69d1eae8b485@denx.de> Date: Fri, 2 Dec 2022 13:21:48 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.5.0 Subject: Re: [PATCH v8 06/14] drm: bridge: samsung-dsim: Handle proper DSI host initialization Content-Language: en-US To: Marek Szyprowski , Jagan Teki Cc: Andrzej Hajda , Inki Dae , Joonyoung Shim , Seung-Woo Kim , Kyungmin Park , Frieder Schrempf , Fancy Fang , Tim Harvey , Michael Nazzareno Trimarchi , Adam Ford , Neil Armstrong , Robert Foss , Laurent Pinchart , Tommaso Merciai , Matteo Lisi , dri-devel@lists.freedesktop.org, linux-samsung-soc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, NXP Linux Team , linux-amarula , Dave Stevenson References: <20221110183853.3678209-1-jagan@amarulasolutions.com> <20221110183853.3678209-7-jagan@amarulasolutions.com> <04fb17e2-1b55-fbd9-d846-da3e3da4edb8@denx.de> <58671662-9242-c7ef-53ef-60f9cdc3399a@denx.de> <9f08a902-049c-1c00-7fed-3d7ee18b3d2c@samsung.com> From: Marek Vasut In-Reply-To: <9f08a902-049c-1c00-7fed-3d7ee18b3d2c@samsung.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: clamav-milter 0.103.6 at phobos.denx.de X-Virus-Status: Clean Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@vger.kernel.org On 12/2/22 11:52, Marek Szyprowski wrote: > Hi, > > Sorry for delay, I was on a sick leave last 2 weeks. > > On 28.11.2022 15:43, Jagan Teki wrote: >> ,On Sat, Nov 26, 2022 at 3:44 AM Marek Vasut wrote: >>> On 11/23/22 21:09, Jagan Teki wrote: >>>> On Sat, Nov 19, 2022 at 7:45 PM Marek Vasut wrote: >>>>> On 11/17/22 14:04, Marek Szyprowski wrote: >>>>>> On 17.11.2022 05:58, Marek Vasut wrote: >>>>>>> On 11/10/22 19:38, Jagan Teki wrote: >>>>>>>> DSI host initialization handling in previous exynos dsi driver has >>>>>>>> some pitfalls. It initializes the host during host transfer() hook >>>>>>>> that is indeed not the desired call flow for I2C and any other DSI >>>>>>>> configured downstream bridges. >>>>>>>> >>>>>>>> Host transfer() is usually triggered for downstream DSI panels or >>>>>>>> bridges and I2C-configured-DSI bridges miss these host initialization >>>>>>>> as these downstream bridges use bridge operations hooks like pre_enable, >>>>>>>> and enable in order to initialize or set up the host. >>>>>>>> >>>>>>>> This patch is trying to handle the host init handler to satisfy all >>>>>>>> downstream panels and bridges. Added the DSIM_STATE_REINITIALIZED state >>>>>>>> flag to ensure that host init is also done on first cmd transfer, this >>>>>>>> helps existing DSI panels work on exynos platform (form Marek >>>>>>>> Szyprowski). >>>>>>>> >>>>>>>> v8, v7, v6, v5: >>>>>>>> * none >>>>>>>> >>>>>>>> v4: >>>>>>>> * update init handling to ensure host init done on first cmd transfer >>>>>>>> >>>>>>>> v3: >>>>>>>> * none >>>>>>>> >>>>>>>> v2: >>>>>>>> * check initialized state in samsung_dsim_init >>>>>>>> >>>>>>>> v1: >>>>>>>> * keep DSI init in host transfer >>>>>>>> >>>>>>>> Signed-off-by: Marek Szyprowski >>>>>>>> Signed-off-by: Jagan Teki >>>>>>>> --- >>>>>>>> drivers/gpu/drm/bridge/samsung-dsim.c | 25 +++++++++++++++++-------- >>>>>>>> include/drm/bridge/samsung-dsim.h | 5 +++-- >>>>>>>> 2 files changed, 20 insertions(+), 10 deletions(-) >>>>>>>> >>>>>>>> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c >>>>>>>> b/drivers/gpu/drm/bridge/samsung-dsim.c >>>>>>>> index bb1f45fd5a88..ec7e01ae02ea 100644 >>>>>>>> --- a/drivers/gpu/drm/bridge/samsung-dsim.c >>>>>>>> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c >>>>>>>> @@ -1234,12 +1234,17 @@ static void samsung_dsim_disable_irq(struct >>>>>>>> samsung_dsim *dsi) >>>>>>>> disable_irq(dsi->irq); >>>>>>>> } >>>>>>>> -static int samsung_dsim_init(struct samsung_dsim *dsi) >>>>>>>> +static int samsung_dsim_init(struct samsung_dsim *dsi, unsigned int >>>>>>>> flag) >>>>>>>> { >>>>>>>> const struct samsung_dsim_driver_data *driver_data = >>>>>>>> dsi->driver_data; >>>>>>>> + if (dsi->state & flag) >>>>>>>> + return 0; >>>>>>>> + >>>>>>>> samsung_dsim_reset(dsi); >>>>>>>> - samsung_dsim_enable_irq(dsi); >>>>>>>> + >>>>>>>> + if (!(dsi->state & DSIM_STATE_INITIALIZED)) >>>>>>>> + samsung_dsim_enable_irq(dsi); >>>>>>>> if (driver_data->reg_values[RESET_TYPE] == DSIM_FUNCRST) >>>>>>>> samsung_dsim_enable_lane(dsi, BIT(dsi->lanes) - 1); >>>>>>>> @@ -1250,6 +1255,8 @@ static int samsung_dsim_init(struct >>>>>>>> samsung_dsim *dsi) >>>>>>>> samsung_dsim_set_phy_ctrl(dsi); >>>>>>>> samsung_dsim_init_link(dsi); >>>>>>>> + dsi->state |= flag; >>>>>>>> + >>>>>>>> return 0; >>>>>>>> } >>>>>>>> @@ -1269,6 +1276,10 @@ static void >>>>>>>> samsung_dsim_atomic_pre_enable(struct drm_bridge *bridge, >>>>>>>> } >>>>>>>> dsi->state |= DSIM_STATE_ENABLED; >>>>>>>> + >>>>>>>> + ret = samsung_dsim_init(dsi, DSIM_STATE_INITIALIZED); >>>>>>>> + if (ret) >>>>>>>> + return; >>>>>>>> } >>>>>>>> static void samsung_dsim_atomic_enable(struct drm_bridge *bridge, >>>>>>>> @@ -1458,12 +1469,9 @@ static ssize_t >>>>>>>> samsung_dsim_host_transfer(struct mipi_dsi_host *host, >>>>>>>> if (!(dsi->state & DSIM_STATE_ENABLED)) >>>>>>>> return -EINVAL; >>>>>>>> - if (!(dsi->state & DSIM_STATE_INITIALIZED)) { >>>>>>>> - ret = samsung_dsim_init(dsi); >>>>>>>> - if (ret) >>>>>>>> - return ret; >>>>>>>> - dsi->state |= DSIM_STATE_INITIALIZED; >>>>>>>> - } >>>>>>>> + ret = samsung_dsim_init(dsi, DSIM_STATE_REINITIALIZED); >>>>>>> This triggers full controller reset and reprogramming upon first >>>>>>> command transfer, is such heavy handed reload really necessary ? >>>>>> Yes it is, otherwise the proper DSI panels doesn't work with Exynos DRM >>>>>> DSI. If this is a real issue for you, then maybe the driver could do the >>>>>> initialization conditionally, in prepare() callback in case of IMX and >>>>>> on the first transfer in case of Exynos? >>>>> That's odd , it does actually break panel support for me, without this >>>>> double reset the panel works again. But I have to wonder, why would such >>>>> a full reset be necessary at all , even on the exynos ? >>>> Is it breaking samsung_dsim_reset from host_transfer? maybe checking >>>> whether a reset is required before calling it might fix the issue. I >>>> agree with double initialization is odd but it seems it is required on >>>> some panels in Exynos, I think tweaking them and adjusting the panel >>>> code might resolve this discrepancy. >>> Can someone provide further details on the exynos problem ? >> If I'm correct this sequence is required in order to work the existing >> panel/bridges on exynos. Adjusting these panel/bridge codes can >> possibly fix the sequence further. >> >> Marek Szyprowski, please add if you have anything. > > > Well, frankly speaking the double initialization is not a correct > sequence, but this is the only one that actually works on Exynos based > boards with DSI panels after moving the initialization to bridge's > .prepare() callback. Somehow, I suspect this is related to the LP11 mode handling, which differs for different panels, right ? I think the RPi people worked on fixing that. +CC Dave > I've already explained this and shared the results > of my investigation in my replies to the previous versions of this > patchset. The original Exynos DSI driver does the initialization on the > first DSI command. This however doesn't work for Jagan with I2C > controlled panels/bridges, so he moved the initialization to the > .prepare() callback, what broke the Exynos case (in-short - all tested > panels works fine only if the DSI host initialization is done AFTER > turning the panel's power on). For more information, see this thread: > https://lore.kernel.org/all/e96197f9-948a-997e-5453-9f9d179b5f5a@samsung.com/ > > Now, the more I think of it, the more I'm convinced that we simply > should add a hack based on the HW type: do the initialization in > .prepare() for non-Exynos case and before the first transfer for the > Exynos case, as there is no way to detect the panel/next bridge type > (I2C or DSI controlled). Let's see what Dave has to say about this, maybe there is some further help. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5BA90C4321E for ; Fri, 2 Dec 2022 12:21:56 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 1CEB510E0AA; Fri, 2 Dec 2022 12:21:54 +0000 (UTC) Received: from phobos.denx.de (phobos.denx.de [IPv6:2a01:238:438b:c500:173d:9f52:ddab:ee01]) by gabe.freedesktop.org (Postfix) with ESMTPS id 4FFEE10E0AA for ; Fri, 2 Dec 2022 12:21:52 +0000 (UTC) Received: from [127.0.0.1] (p578adb1c.dip0.t-ipconnect.de [87.138.219.28]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: marex@denx.de) by phobos.denx.de (Postfix) with ESMTPSA id E5CCF84F62; Fri, 2 Dec 2022 13:21:48 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=denx.de; s=phobos-20191101; t=1669983710; bh=DAGUPW1K0fo7i5LI1mBlSSU7CpoTBUXsHq+pagui1DQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=FvfjKoXx+k1LZiSiqRqrx6bAYqdCqJsjUKXcECsFyAt3MVdHtezuJjbgguSjD+fG3 mb5n+/k58PklYuB4tNTJOIhI5dfXqIUpRATUPq/uGrDlZWB5P9W2TpFDiEk7IOEM/l z66Zac9f2KnAlroqrhEBH1Iedw+fMEmpAcLAJIVxIU3V2wE+EyIFcLHpPJktl7Obuk yjhiGAo/DlWvIgkhnmuFzYZi1CLOoALdi27xunKqVX99g4R9x/y2Jk8xcCAgeec0ux 7I0EegmjFdQkpzLlfm1uHOnk9kq/ndI/odUlaBrlQ73nlSyCob7nRzL3F8jaINcJoh 5TfnoUBI5+7Kg== Message-ID: <2ef1aae1-8ff9-22bc-9817-69d1eae8b485@denx.de> Date: Fri, 2 Dec 2022 13:21:48 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.5.0 Subject: Re: [PATCH v8 06/14] drm: bridge: samsung-dsim: Handle proper DSI host initialization Content-Language: en-US To: Marek Szyprowski , Jagan Teki References: <20221110183853.3678209-1-jagan@amarulasolutions.com> <20221110183853.3678209-7-jagan@amarulasolutions.com> <04fb17e2-1b55-fbd9-d846-da3e3da4edb8@denx.de> <58671662-9242-c7ef-53ef-60f9cdc3399a@denx.de> <9f08a902-049c-1c00-7fed-3d7ee18b3d2c@samsung.com> From: Marek Vasut In-Reply-To: <9f08a902-049c-1c00-7fed-3d7ee18b3d2c@samsung.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: clamav-milter 0.103.6 at phobos.denx.de X-Virus-Status: Clean X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: dri-devel@lists.freedesktop.org, linux-samsung-soc@vger.kernel.org, Joonyoung Shim , Tommaso Merciai , linux-amarula , Dave Stevenson , Seung-Woo Kim , Neil Armstrong , Frieder Schrempf , Kyungmin Park , Matteo Lisi , Robert Foss , Andrzej Hajda , NXP Linux Team , Fancy Fang , Michael Nazzareno Trimarchi , Adam Ford , linux-arm-kernel@lists.infradead.org, Laurent Pinchart Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 12/2/22 11:52, Marek Szyprowski wrote: > Hi, > > Sorry for delay, I was on a sick leave last 2 weeks. > > On 28.11.2022 15:43, Jagan Teki wrote: >> ,On Sat, Nov 26, 2022 at 3:44 AM Marek Vasut wrote: >>> On 11/23/22 21:09, Jagan Teki wrote: >>>> On Sat, Nov 19, 2022 at 7:45 PM Marek Vasut wrote: >>>>> On 11/17/22 14:04, Marek Szyprowski wrote: >>>>>> On 17.11.2022 05:58, Marek Vasut wrote: >>>>>>> On 11/10/22 19:38, Jagan Teki wrote: >>>>>>>> DSI host initialization handling in previous exynos dsi driver has >>>>>>>> some pitfalls. It initializes the host during host transfer() hook >>>>>>>> that is indeed not the desired call flow for I2C and any other DSI >>>>>>>> configured downstream bridges. >>>>>>>> >>>>>>>> Host transfer() is usually triggered for downstream DSI panels or >>>>>>>> bridges and I2C-configured-DSI bridges miss these host initialization >>>>>>>> as these downstream bridges use bridge operations hooks like pre_enable, >>>>>>>> and enable in order to initialize or set up the host. >>>>>>>> >>>>>>>> This patch is trying to handle the host init handler to satisfy all >>>>>>>> downstream panels and bridges. Added the DSIM_STATE_REINITIALIZED state >>>>>>>> flag to ensure that host init is also done on first cmd transfer, this >>>>>>>> helps existing DSI panels work on exynos platform (form Marek >>>>>>>> Szyprowski). >>>>>>>> >>>>>>>> v8, v7, v6, v5: >>>>>>>> * none >>>>>>>> >>>>>>>> v4: >>>>>>>> * update init handling to ensure host init done on first cmd transfer >>>>>>>> >>>>>>>> v3: >>>>>>>> * none >>>>>>>> >>>>>>>> v2: >>>>>>>> * check initialized state in samsung_dsim_init >>>>>>>> >>>>>>>> v1: >>>>>>>> * keep DSI init in host transfer >>>>>>>> >>>>>>>> Signed-off-by: Marek Szyprowski >>>>>>>> Signed-off-by: Jagan Teki >>>>>>>> --- >>>>>>>> drivers/gpu/drm/bridge/samsung-dsim.c | 25 +++++++++++++++++-------- >>>>>>>> include/drm/bridge/samsung-dsim.h | 5 +++-- >>>>>>>> 2 files changed, 20 insertions(+), 10 deletions(-) >>>>>>>> >>>>>>>> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c >>>>>>>> b/drivers/gpu/drm/bridge/samsung-dsim.c >>>>>>>> index bb1f45fd5a88..ec7e01ae02ea 100644 >>>>>>>> --- a/drivers/gpu/drm/bridge/samsung-dsim.c >>>>>>>> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c >>>>>>>> @@ -1234,12 +1234,17 @@ static void samsung_dsim_disable_irq(struct >>>>>>>> samsung_dsim *dsi) >>>>>>>> disable_irq(dsi->irq); >>>>>>>> } >>>>>>>> -static int samsung_dsim_init(struct samsung_dsim *dsi) >>>>>>>> +static int samsung_dsim_init(struct samsung_dsim *dsi, unsigned int >>>>>>>> flag) >>>>>>>> { >>>>>>>> const struct samsung_dsim_driver_data *driver_data = >>>>>>>> dsi->driver_data; >>>>>>>> + if (dsi->state & flag) >>>>>>>> + return 0; >>>>>>>> + >>>>>>>> samsung_dsim_reset(dsi); >>>>>>>> - samsung_dsim_enable_irq(dsi); >>>>>>>> + >>>>>>>> + if (!(dsi->state & DSIM_STATE_INITIALIZED)) >>>>>>>> + samsung_dsim_enable_irq(dsi); >>>>>>>> if (driver_data->reg_values[RESET_TYPE] == DSIM_FUNCRST) >>>>>>>> samsung_dsim_enable_lane(dsi, BIT(dsi->lanes) - 1); >>>>>>>> @@ -1250,6 +1255,8 @@ static int samsung_dsim_init(struct >>>>>>>> samsung_dsim *dsi) >>>>>>>> samsung_dsim_set_phy_ctrl(dsi); >>>>>>>> samsung_dsim_init_link(dsi); >>>>>>>> + dsi->state |= flag; >>>>>>>> + >>>>>>>> return 0; >>>>>>>> } >>>>>>>> @@ -1269,6 +1276,10 @@ static void >>>>>>>> samsung_dsim_atomic_pre_enable(struct drm_bridge *bridge, >>>>>>>> } >>>>>>>> dsi->state |= DSIM_STATE_ENABLED; >>>>>>>> + >>>>>>>> + ret = samsung_dsim_init(dsi, DSIM_STATE_INITIALIZED); >>>>>>>> + if (ret) >>>>>>>> + return; >>>>>>>> } >>>>>>>> static void samsung_dsim_atomic_enable(struct drm_bridge *bridge, >>>>>>>> @@ -1458,12 +1469,9 @@ static ssize_t >>>>>>>> samsung_dsim_host_transfer(struct mipi_dsi_host *host, >>>>>>>> if (!(dsi->state & DSIM_STATE_ENABLED)) >>>>>>>> return -EINVAL; >>>>>>>> - if (!(dsi->state & DSIM_STATE_INITIALIZED)) { >>>>>>>> - ret = samsung_dsim_init(dsi); >>>>>>>> - if (ret) >>>>>>>> - return ret; >>>>>>>> - dsi->state |= DSIM_STATE_INITIALIZED; >>>>>>>> - } >>>>>>>> + ret = samsung_dsim_init(dsi, DSIM_STATE_REINITIALIZED); >>>>>>> This triggers full controller reset and reprogramming upon first >>>>>>> command transfer, is such heavy handed reload really necessary ? >>>>>> Yes it is, otherwise the proper DSI panels doesn't work with Exynos DRM >>>>>> DSI. If this is a real issue for you, then maybe the driver could do the >>>>>> initialization conditionally, in prepare() callback in case of IMX and >>>>>> on the first transfer in case of Exynos? >>>>> That's odd , it does actually break panel support for me, without this >>>>> double reset the panel works again. But I have to wonder, why would such >>>>> a full reset be necessary at all , even on the exynos ? >>>> Is it breaking samsung_dsim_reset from host_transfer? maybe checking >>>> whether a reset is required before calling it might fix the issue. I >>>> agree with double initialization is odd but it seems it is required on >>>> some panels in Exynos, I think tweaking them and adjusting the panel >>>> code might resolve this discrepancy. >>> Can someone provide further details on the exynos problem ? >> If I'm correct this sequence is required in order to work the existing >> panel/bridges on exynos. Adjusting these panel/bridge codes can >> possibly fix the sequence further. >> >> Marek Szyprowski, please add if you have anything. > > > Well, frankly speaking the double initialization is not a correct > sequence, but this is the only one that actually works on Exynos based > boards with DSI panels after moving the initialization to bridge's > .prepare() callback. Somehow, I suspect this is related to the LP11 mode handling, which differs for different panels, right ? I think the RPi people worked on fixing that. +CC Dave > I've already explained this and shared the results > of my investigation in my replies to the previous versions of this > patchset. The original Exynos DSI driver does the initialization on the > first DSI command. This however doesn't work for Jagan with I2C > controlled panels/bridges, so he moved the initialization to the > .prepare() callback, what broke the Exynos case (in-short - all tested > panels works fine only if the DSI host initialization is done AFTER > turning the panel's power on). For more information, see this thread: > https://lore.kernel.org/all/e96197f9-948a-997e-5453-9f9d179b5f5a@samsung.com/ > > Now, the more I think of it, the more I'm convinced that we simply > should add a hack based on the HW type: do the initialization in > .prepare() for non-Exynos case and before the first transfer for the > Exynos case, as there is no way to detect the panel/next bridge type > (I2C or DSI controlled). Let's see what Dave has to say about this, maybe there is some further help. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DF335C4321E for ; Fri, 2 Dec 2022 12:23:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=pEsyg6pH1GcKMxt8ssfd7ybNUzWz/YvNq03ix5QqLsQ=; b=Mg6rY8gTPsV/JH 4OvqWWxaFZIH3a71SDu8FyFrYEwnyiuyt4GzU2qv3ApluecUPoJPSMSrnNOUTayOLrDenfGZBUE83 R3eTK2ZugXuuremQffvjyokuva8uVonyhb8gExFWMPmXPG8vCXSZK1X4lqEPQPBitrdszGVtvoDe6 y04Q2wgkzZERU+qPGNOOmmp0esolmpUiAxIICQCOPU/KYP0JyQG4Ly1axKa6QRUXk3iBqa7WA/CFX uvScVA9tIwNip1r3+pzaLdfF6RDMrWsUgOHgpZnIZH0YtbmlI5HIwdbBiJKzoLJD8jzIUWwypm6N/ e9XAAi/VP5MuSL/K+DxQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p153M-00GIeN-GF; Fri, 02 Dec 2022 12:22:05 +0000 Received: from phobos.denx.de ([2a01:238:438b:c500:173d:9f52:ddab:ee01]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1p153E-00GIaO-A0 for linux-arm-kernel@lists.infradead.org; Fri, 02 Dec 2022 12:21:58 +0000 Received: from [127.0.0.1] (p578adb1c.dip0.t-ipconnect.de [87.138.219.28]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: marex@denx.de) by phobos.denx.de (Postfix) with ESMTPSA id E5CCF84F62; Fri, 2 Dec 2022 13:21:48 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=denx.de; s=phobos-20191101; t=1669983710; bh=DAGUPW1K0fo7i5LI1mBlSSU7CpoTBUXsHq+pagui1DQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=FvfjKoXx+k1LZiSiqRqrx6bAYqdCqJsjUKXcECsFyAt3MVdHtezuJjbgguSjD+fG3 mb5n+/k58PklYuB4tNTJOIhI5dfXqIUpRATUPq/uGrDlZWB5P9W2TpFDiEk7IOEM/l z66Zac9f2KnAlroqrhEBH1Iedw+fMEmpAcLAJIVxIU3V2wE+EyIFcLHpPJktl7Obuk yjhiGAo/DlWvIgkhnmuFzYZi1CLOoALdi27xunKqVX99g4R9x/y2Jk8xcCAgeec0ux 7I0EegmjFdQkpzLlfm1uHOnk9kq/ndI/odUlaBrlQ73nlSyCob7nRzL3F8jaINcJoh 5TfnoUBI5+7Kg== Message-ID: <2ef1aae1-8ff9-22bc-9817-69d1eae8b485@denx.de> Date: Fri, 2 Dec 2022 13:21:48 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.5.0 Subject: Re: [PATCH v8 06/14] drm: bridge: samsung-dsim: Handle proper DSI host initialization Content-Language: en-US To: Marek Szyprowski , Jagan Teki Cc: Andrzej Hajda , Inki Dae , Joonyoung Shim , Seung-Woo Kim , Kyungmin Park , Frieder Schrempf , Fancy Fang , Tim Harvey , Michael Nazzareno Trimarchi , Adam Ford , Neil Armstrong , Robert Foss , Laurent Pinchart , Tommaso Merciai , Matteo Lisi , dri-devel@lists.freedesktop.org, linux-samsung-soc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, NXP Linux Team , linux-amarula , Dave Stevenson References: <20221110183853.3678209-1-jagan@amarulasolutions.com> <20221110183853.3678209-7-jagan@amarulasolutions.com> <04fb17e2-1b55-fbd9-d846-da3e3da4edb8@denx.de> <58671662-9242-c7ef-53ef-60f9cdc3399a@denx.de> <9f08a902-049c-1c00-7fed-3d7ee18b3d2c@samsung.com> From: Marek Vasut In-Reply-To: <9f08a902-049c-1c00-7fed-3d7ee18b3d2c@samsung.com> X-Virus-Scanned: clamav-milter 0.103.6 at phobos.denx.de X-Virus-Status: Clean X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221202_042156_819983_506509BE X-CRM114-Status: GOOD ( 37.71 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 12/2/22 11:52, Marek Szyprowski wrote: > Hi, > > Sorry for delay, I was on a sick leave last 2 weeks. > > On 28.11.2022 15:43, Jagan Teki wrote: >> ,On Sat, Nov 26, 2022 at 3:44 AM Marek Vasut wrote: >>> On 11/23/22 21:09, Jagan Teki wrote: >>>> On Sat, Nov 19, 2022 at 7:45 PM Marek Vasut wrote: >>>>> On 11/17/22 14:04, Marek Szyprowski wrote: >>>>>> On 17.11.2022 05:58, Marek Vasut wrote: >>>>>>> On 11/10/22 19:38, Jagan Teki wrote: >>>>>>>> DSI host initialization handling in previous exynos dsi driver has >>>>>>>> some pitfalls. It initializes the host during host transfer() hook >>>>>>>> that is indeed not the desired call flow for I2C and any other DSI >>>>>>>> configured downstream bridges. >>>>>>>> >>>>>>>> Host transfer() is usually triggered for downstream DSI panels or >>>>>>>> bridges and I2C-configured-DSI bridges miss these host initialization >>>>>>>> as these downstream bridges use bridge operations hooks like pre_enable, >>>>>>>> and enable in order to initialize or set up the host. >>>>>>>> >>>>>>>> This patch is trying to handle the host init handler to satisfy all >>>>>>>> downstream panels and bridges. Added the DSIM_STATE_REINITIALIZED state >>>>>>>> flag to ensure that host init is also done on first cmd transfer, this >>>>>>>> helps existing DSI panels work on exynos platform (form Marek >>>>>>>> Szyprowski). >>>>>>>> >>>>>>>> v8, v7, v6, v5: >>>>>>>> * none >>>>>>>> >>>>>>>> v4: >>>>>>>> * update init handling to ensure host init done on first cmd transfer >>>>>>>> >>>>>>>> v3: >>>>>>>> * none >>>>>>>> >>>>>>>> v2: >>>>>>>> * check initialized state in samsung_dsim_init >>>>>>>> >>>>>>>> v1: >>>>>>>> * keep DSI init in host transfer >>>>>>>> >>>>>>>> Signed-off-by: Marek Szyprowski >>>>>>>> Signed-off-by: Jagan Teki >>>>>>>> --- >>>>>>>> drivers/gpu/drm/bridge/samsung-dsim.c | 25 +++++++++++++++++-------- >>>>>>>> include/drm/bridge/samsung-dsim.h | 5 +++-- >>>>>>>> 2 files changed, 20 insertions(+), 10 deletions(-) >>>>>>>> >>>>>>>> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c >>>>>>>> b/drivers/gpu/drm/bridge/samsung-dsim.c >>>>>>>> index bb1f45fd5a88..ec7e01ae02ea 100644 >>>>>>>> --- a/drivers/gpu/drm/bridge/samsung-dsim.c >>>>>>>> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c >>>>>>>> @@ -1234,12 +1234,17 @@ static void samsung_dsim_disable_irq(struct >>>>>>>> samsung_dsim *dsi) >>>>>>>> disable_irq(dsi->irq); >>>>>>>> } >>>>>>>> -static int samsung_dsim_init(struct samsung_dsim *dsi) >>>>>>>> +static int samsung_dsim_init(struct samsung_dsim *dsi, unsigned int >>>>>>>> flag) >>>>>>>> { >>>>>>>> const struct samsung_dsim_driver_data *driver_data = >>>>>>>> dsi->driver_data; >>>>>>>> + if (dsi->state & flag) >>>>>>>> + return 0; >>>>>>>> + >>>>>>>> samsung_dsim_reset(dsi); >>>>>>>> - samsung_dsim_enable_irq(dsi); >>>>>>>> + >>>>>>>> + if (!(dsi->state & DSIM_STATE_INITIALIZED)) >>>>>>>> + samsung_dsim_enable_irq(dsi); >>>>>>>> if (driver_data->reg_values[RESET_TYPE] == DSIM_FUNCRST) >>>>>>>> samsung_dsim_enable_lane(dsi, BIT(dsi->lanes) - 1); >>>>>>>> @@ -1250,6 +1255,8 @@ static int samsung_dsim_init(struct >>>>>>>> samsung_dsim *dsi) >>>>>>>> samsung_dsim_set_phy_ctrl(dsi); >>>>>>>> samsung_dsim_init_link(dsi); >>>>>>>> + dsi->state |= flag; >>>>>>>> + >>>>>>>> return 0; >>>>>>>> } >>>>>>>> @@ -1269,6 +1276,10 @@ static void >>>>>>>> samsung_dsim_atomic_pre_enable(struct drm_bridge *bridge, >>>>>>>> } >>>>>>>> dsi->state |= DSIM_STATE_ENABLED; >>>>>>>> + >>>>>>>> + ret = samsung_dsim_init(dsi, DSIM_STATE_INITIALIZED); >>>>>>>> + if (ret) >>>>>>>> + return; >>>>>>>> } >>>>>>>> static void samsung_dsim_atomic_enable(struct drm_bridge *bridge, >>>>>>>> @@ -1458,12 +1469,9 @@ static ssize_t >>>>>>>> samsung_dsim_host_transfer(struct mipi_dsi_host *host, >>>>>>>> if (!(dsi->state & DSIM_STATE_ENABLED)) >>>>>>>> return -EINVAL; >>>>>>>> - if (!(dsi->state & DSIM_STATE_INITIALIZED)) { >>>>>>>> - ret = samsung_dsim_init(dsi); >>>>>>>> - if (ret) >>>>>>>> - return ret; >>>>>>>> - dsi->state |= DSIM_STATE_INITIALIZED; >>>>>>>> - } >>>>>>>> + ret = samsung_dsim_init(dsi, DSIM_STATE_REINITIALIZED); >>>>>>> This triggers full controller reset and reprogramming upon first >>>>>>> command transfer, is such heavy handed reload really necessary ? >>>>>> Yes it is, otherwise the proper DSI panels doesn't work with Exynos DRM >>>>>> DSI. If this is a real issue for you, then maybe the driver could do the >>>>>> initialization conditionally, in prepare() callback in case of IMX and >>>>>> on the first transfer in case of Exynos? >>>>> That's odd , it does actually break panel support for me, without this >>>>> double reset the panel works again. But I have to wonder, why would such >>>>> a full reset be necessary at all , even on the exynos ? >>>> Is it breaking samsung_dsim_reset from host_transfer? maybe checking >>>> whether a reset is required before calling it might fix the issue. I >>>> agree with double initialization is odd but it seems it is required on >>>> some panels in Exynos, I think tweaking them and adjusting the panel >>>> code might resolve this discrepancy. >>> Can someone provide further details on the exynos problem ? >> If I'm correct this sequence is required in order to work the existing >> panel/bridges on exynos. Adjusting these panel/bridge codes can >> possibly fix the sequence further. >> >> Marek Szyprowski, please add if you have anything. > > > Well, frankly speaking the double initialization is not a correct > sequence, but this is the only one that actually works on Exynos based > boards with DSI panels after moving the initialization to bridge's > .prepare() callback. Somehow, I suspect this is related to the LP11 mode handling, which differs for different panels, right ? I think the RPi people worked on fixing that. +CC Dave > I've already explained this and shared the results > of my investigation in my replies to the previous versions of this > patchset. The original Exynos DSI driver does the initialization on the > first DSI command. This however doesn't work for Jagan with I2C > controlled panels/bridges, so he moved the initialization to the > .prepare() callback, what broke the Exynos case (in-short - all tested > panels works fine only if the DSI host initialization is done AFTER > turning the panel's power on). For more information, see this thread: > https://lore.kernel.org/all/e96197f9-948a-997e-5453-9f9d179b5f5a@samsung.com/ > > Now, the more I think of it, the more I'm convinced that we simply > should add a hack based on the HW type: do the initialization in > .prepare() for non-Exynos case and before the first transfer for the > Exynos case, as there is no way to detect the panel/next bridge type > (I2C or DSI controlled). Let's see what Dave has to say about this, maybe there is some further help. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel