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 DA6F3C433F5 for ; Tue, 8 Feb 2022 09:04:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352857AbiBHJEG (ORCPT ); Tue, 8 Feb 2022 04:04:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52094 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237702AbiBHJEE (ORCPT ); Tue, 8 Feb 2022 04:04:04 -0500 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6EF63C03FEC0; Tue, 8 Feb 2022 01:04:03 -0800 (PST) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: kholk11) with ESMTPSA id 5ED6B1F4474E DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1644311042; bh=9sgJPXTqfK75Hu2kDZUDOsgZGJfuQ/MhsF+51PqY9d8=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=cxeCpY9JpTWim2lNGoN3hul0SMhHdA/NQydI8he7rdyfhWY7N9QUuad1cg8/AY4EW E55D03ZuSDgOfbQo4tRF+hDHOQ2ew1uqD3KM63YuMNQjiS/tdWjLKKh5/1VY6lipsm qEdIcTrFzLViuTltNWGVYE8IksuFoKoGdyXIw0n6DgNseDxH9jb+vFIbW3bvH6kAK4 gWmHxHi/8YMCppgoaUyjEncsnx7jK9hhehV6oZp0HyEw37HccDD37SONlwwcufc+KW O4YMvTxxPVG/z2Sxymn98QaaU75LOL234XZt1qXP0oqe2GItnewSEEqfgAVwFpELgh lmXub2km4nYnQ== Message-ID: Date: Tue, 8 Feb 2022 10:03:58 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.1 Subject: Re: [PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge Content-Language: en-US To: CK Hu , dri-devel@lists.freedesktop.org Cc: chunkuang.hu@kernel.org, airlied@linux.ie, linux-kernel@vger.kernel.org, stable@vger.kernel.org, andrzej.hajda@intel.com, linux-mediatek@lists.infradead.org, Jagan Teki , matthias.bgg@gmail.com, kernel@collabora.com, linux-arm-kernel@lists.infradead.org References: <20220131085520.287105-1-angelogioacchino.delregno@collabora.com> <20755168cc2be0d1bb5e40907cfe27cea25a9363.camel@mediatek.com> From: AngeloGioacchino Del Regno In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 08/02/22 09:32, CK Hu ha scritto: > Hi, Angelo: > > On Tue, 2022-02-08 at 16:20 +0800, CK Hu wrote: >> Hi, Angelo: >> >> On Mon, 2022-01-31 at 09:55 +0100, AngeloGioacchino Del Regno wrote: >>> DRM bridge drivers are now attaching their DSI device at probe >>> time, >>> which requires us to register our DSI host in order to let the >>> bridge >>> to probe: this recently started producing an endless -EPROBE_DEFER >>> loop on some machines that are using external bridges, like the >>> parade-ps8640, found on the ACER Chromebook R13. >>> >>> Now that the DSI hosts/devices probe sequence is documented, we can >>> do adjustments to the mtk_dsi driver as to both fix now and make >>> sure >>> to avoid this situation in the future: for this, following what is >>> documented in drm_bridge.c, move the mtk_dsi component_add() to the >>> mtk_dsi_ops.attach callback and delete it in the detach callback; >>> keeping in mind that we are registering a drm_bridge for our DSI, >>> which is only used/attached if the DSI Host is bound, it wouldn't >>> make sense to keep adding our bridge at probe time (as it would >>> be useless to have it if mtk_dsi_ops.attach() fails!), so also move >>> that one to the dsi host attach function (and remove it in detach). >>> >>> Cc: # 5.15.x >>> Signed-off-by: AngeloGioacchino Del Regno < >>> angelogioacchino.delregno@collabora.com> >>> Reviewed-by: Andrzej Hajda >>> Reviewed-by: Jagan Teki >>> >>> --- >>> drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++---------- >>> ---- >>> 1 file changed, 84 insertions(+), 83 deletions(-) >>> >>> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c >>> b/drivers/gpu/drm/mediatek/mtk_dsi.c >>> index 5d90d2eb0019..bced4c7d668e 100644 >>> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c >>> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c >>> @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev) >>> mtk_dsi_poweroff(dsi); >>> } >>> >>> >> >> [snip] >> >>> + >>> static int mtk_dsi_host_attach(struct mipi_dsi_host *host, >>> struct mipi_dsi_device *device) >>> { >>> struct mtk_dsi *dsi = host_to_dsi(host); >>> + struct device *dev = host->dev; >>> + int ret; >>> >>> dsi->lanes = device->lanes; >>> dsi->format = device->format; >>> dsi->mode_flags = device->mode_flags; >>> + dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, >>> 0); >> >> The original would process panel. Why do you remove the panel part? >> It's better that someone has a platform of DSI->Panel to test this >> patch. > > Sorry, devm_drm_of_get_bridge() has processed the panel part, so for > this patch, > > Reviewed-by: CK Hu > No worries! Thanks for the review/approval. Regards, Angelo >> >> Regards, >> CK >>