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 CA9A1C4332F for ; Thu, 8 Dec 2022 11:33:45 +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-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:Subject:Message-ID:Date:From: In-Reply-To:References:MIME-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=teU/YKlnSCYpKF1+vmlZ6H73S1XJN5HZiFaHlCkS1ec=; b=qFFt7qJT9dAdo6 hYmj9JPQyeF8LQLsFkTXeIt3i3RbDCKA+ehgh93EgjdmuyAoFx1G8DFhnOv271HvCg9ARdBVm96u8 q7jtKNkl0YQ+bfmcvKGpeu7WPc/Fc4dCt/ClYRq4XwgqOqwtW4DNClKcgNL86AqVvhO0Efs3W9Y9t jRoAWWIBLv4mw3j0SesmZC2hQQXIXsnTZmN8zSefopf07GYYwAOCLjhhMm1Rdriag9lMeB74n98k1 i70zc0n7UQ5HwwRRleK+kOhB0OHFjI3mheljEelZCMidPd1c9Dcrim+ZTvj+9+2iwA8XxnY7AOvR4 gp63FBNgtYw0cW3tkksQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p3F8u-00FOGO-8q; Thu, 08 Dec 2022 11:32:44 +0000 Received: from mail-yw1-x1134.google.com ([2607:f8b0:4864:20::1134]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1p3F8p-00FO5C-IM for linux-arm-kernel@lists.infradead.org; Thu, 08 Dec 2022 11:32:42 +0000 Received: by mail-yw1-x1134.google.com with SMTP id 00721157ae682-3b10392c064so11427347b3.0 for ; Thu, 08 Dec 2022 03:32:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amarulasolutions.com; s=google; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=vhZFBV4anZ9F8U1tpTEmxhqV1VbSgjjAY+rE0mwxuBg=; b=DcnYukqkd31K4Ou+0oMg4w3UfKdsMQ9hp07qWNLnESG5BYSNa3LivtkxMXwO2vMQqd Qe8sOLBO3ROZntM2PgDgjiA0YzX7FEDn0ko9OQvRel9GgcFsh2Qf6tXYNVLe44JuEo3n HsyR4SBIMjnhmY1E3FNXB41QzZc1PTYD1sTy0= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=vhZFBV4anZ9F8U1tpTEmxhqV1VbSgjjAY+rE0mwxuBg=; b=6TN3LqhFAFMA/A6Iq8XXCX43dwULvyE7ExedAo01TTwiGRqUHQLrs+9rCSHvno345w K2icV0oGLaouIw1diQr5nKmQ7QV05lNzDAVAMFsDNo18D2dvGxQP1aAXDIODw6NIumLL a+JpYDjHBFrRx6jzrzHh7rLSX2PJp+J5B612JNBeocg5PCL7+pT1IOxrvZF+aBWj+oEf nvCfd/xLjR2agy6r/difTz1xRkvDv2/8z0YTGxu8nFw9ZJ10UzISdxk+B1FR0/AA6K+A kgsRrd9822XkhuE2y5MlrmHSIZF+qrkKFpXzeCW+aEU5LArBMan7ysfFk5L8Ex5Efugd g5SQ== X-Gm-Message-State: ANoB5pn97XqScrAD+zKFVaCtCS5Yq7j+ZbQm+FTGqk18mBRRC1ZOCwmj x4NHOKNdXoIKQ1lfa1+ZllwR4eoC+g9EkUH6ztcbfQ== X-Google-Smtp-Source: AA0mqf4vTvB9Yf1szqHExXlcTm7mc8qW2JJPoGeWqaIbsrATgjSgxDiiaXqtIswGcSY2t4sdLrWUY8t6YHGuGJuHn2w= X-Received: by 2002:a0d:e544:0:b0:392:1434:c329 with SMTP id o65-20020a0de544000000b003921434c329mr6947621ywe.72.1670499155736; Thu, 08 Dec 2022 03:32:35 -0800 (PST) MIME-Version: 1.0 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> <2ef1aae1-8ff9-22bc-9817-69d1eae8b485@denx.de> In-Reply-To: From: Jagan Teki Date: Thu, 8 Dec 2022 17:02:24 +0530 Message-ID: Subject: Re: [PATCH v8 06/14] drm: bridge: samsung-dsim: Handle proper DSI host initialization To: Frieder Schrempf , Marek Szyprowski Cc: Dave Stevenson , Marek Vasut , Andrzej Hajda , Inki Dae , Joonyoung Shim , Seung-Woo Kim , Kyungmin Park , 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221208_033239_694384_D65173D5 X-CRM114-Status: GOOD ( 60.57 ) 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-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Dec 6, 2022 at 2:32 PM Frieder Schrempf wrote: > > On 05.12.22 16:37, Frieder Schrempf wrote: > > Hi Dave, > > > > On 05.12.22 16:20, Dave Stevenson wrote: > >> Hi Frieder > >> > >> On Mon, 5 Dec 2022 at 07:30, Frieder Schrempf > >> wrote: > >>> > >>> On 02.12.22 15:55, Dave Stevenson wrote: > >>>> Hi Marek > >>>> > >>>> On Fri, 2 Dec 2022 at 12:21, Marek Vasut wrote: > >>>>> > >>>>> 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 > >>>> > >>>> Yes. I've just sent out a v3 of that patch set. > >>>> > >>>> Hopefully setting the pre_enable_prev_first flag on your peripheral's > >>>> drm_bridge, or prepare_prev_first if a drm_panel, will result in a > >>>> more sensible initialisation order for your panel. > >>>> > >>>> Note that host_transfer should ensure that the host is initialised, as > >>>> it is valid to call it with the host in any state. If it has to > >>>> initialise, then it should deinitialise once the transfer has > >>>> completed. > >>>> > >>>> 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://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fall%2Fe96197f9-948a-997e-5453-9f9d179b5f5a%40samsung.com%2F&data=05%7C01%7Cfrieder.schrempf%40kontron.de%7Cee7b57ee420e45a73b1d08dad6d45306%7C8c9d3c973fd941c8a2b1646f3942daf1%7C0%7C0%7C638058504671330145%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=TQIIKNa4OVGP1dZo3tM%2FOMO3dlXrjLr04U%2FJFhd2rAs%3D&reserved=0 > >>>>>> > >>>>>> 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. > >>> > >>> Could we agree on adding the HW type based hack Marek S. proposed as a > >>> quick fix? > >>> > >>> This patchset was tested on Exynos so it's likely to not break any > >>> existing setups. And for i.MX8, this is a new driver so there's not > >>> really a requirement to have all setups working/supported from the > >>> beginning. > >>> > >>> Also having one or two hacks (marked with FIXME) in the code doesn't > >>> hurt. As we can see there are drafts to fix them in conjunction with > >>> changes in the DRM framework. > >>> > >>> This has been pending for months and in my opinion if there's a chance > >>> to get this into v6.2-rc1 we should take it. > >> > >> My patchset was sent in March with no one seeming to care enough to review it. > > > > I wasn't referring to your patchset but rather to the Samsung DSIM > > bridge transformation patchset. > > > > My point was simply to not try getting everything done in one big step > > because this will fail. The patchset this refers to needs testing on two > > separate platforms which is painful enough (thanks to Marek for covering > > the Exynos side!). I think we should focus on getting the DSIM bridge > > transformation merged and accept a few small hacks that will be taken > > care of in the next step. > > > >> > >> If the situation is that your devices fall into the same camp as those > >> for vc4 (the host needs to be initialised before the peripheral), at > >> least verifying that would be useful before rushing into a hack. > >> > >> Your other comment references using a TI SN65DSI84. I know for certain > >> that falls into the category of needing the DSI bus initialised before > >> it is brought out of reset. > > > > I'm actually working on this right now and when I received your message > > I was about to start typing a reply to your patchset. > > > > The SN65DSI84 works with the i.MX8MM DSIM even using the default order > > of host init after peripheral init in our setup, but this configuration > > doesn't seem to be stable and occasionally the bridge doesn't come up > > properly. > > > > We are still in the process of verifying if the reversed order fixes > > this reliably. But regardless of the results, without the reversal the > > initialization sequence is way out of spec and we need to fix this in > > any case. > > > > See here for my testing branch including some follow-up patches that > > improve the initialization flow for my setup: > > https://git.kontron-electronics.de/sw/misc/linux/-/commits/v6.1-dsim-mx8mm. > > To recap my thoughts on the two hacks for the DSIM bridge driver > discussed before: > > (1) Passing null to previous bridge in samsung_dsim_attach() > (2) Always initialize host on first transfer (see this patch, 06/14) > > My wild guess would be that both could be fixed up properly in the long > run by the following changes: > > * Apply Dave's patchset [1] > * Set pre_enable_prev_first flag in the downstream bridge drivers and > fix init flow if required ([2] for ti-sn65dsi83) > * Fix DSIM init to keep data lanes in LP11 until enable() is called [3] > * Only call init on transfer when not already initialized and deinit > after transfer (tbd) > > As that route needs proper testing on the affected hardware setups and > includes changes to other drivers and the framework, I would suggest the > following for the v9 of this patchset: I did it on drm-misc-next [1]. > > * Keep hack (1) This has gone, not needed. > * Make hack (2) dependent on the platform (Exynos) I think with pre_enable_prev_first flag the Exynos pipeline will start from bridge funcs like pre_enable so initializing the host will work for exynos to work. [2] Marek Sz. Can you confirm this? [1] https://gitlab.com/openedev/kernel/-/commits/imx8mm-dsi-v9 [2] https://gitlab.com/openedev/kernel/-/commit/95ab71b797310952284fabfbc8476a9831902c5c Jagan. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel