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 38282C433F5 for ; Tue, 5 Apr 2022 11:42:15 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 48A9D10E93D; Tue, 5 Apr 2022 11:42:14 +0000 (UTC) Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by gabe.freedesktop.org (Postfix) with ESMTPS id 7039D10EA3F for ; Tue, 5 Apr 2022 11:42:12 +0000 (UTC) Received: from pendragon.ideasonboard.com (117.145-247-81.adsl-dyn.isp.belgacom.be [81.247.145.117]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 628625D; Tue, 5 Apr 2022 13:42:10 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1649158930; bh=BKnXaDB6e19/u6RKIOfoxvvk14h3gu5uX3laBLbr/CA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kBvDNIiMJnDe9oWAYWfxlZMFMg04btQkTfTU64nm8cxXPZTIfCGnwOcJbZSz8yI/y WQdiUktB/OJAWekI7PafyjzTQVFZfbCTIELbHNdq29gbWOpmo8NNx4SqLFn5j06y6S 3uZyYFQjOSzqlOocRuTrSzRdPREc3TqNbFraX17Y= Date: Tue, 5 Apr 2022 14:42:06 +0300 From: Laurent Pinchart To: Marek Vasut Subject: Re: [PATCH][RESEND] drm/bridge: ti-sn65dsi83: Check link status register after enabling the bridge Message-ID: References: <20220213022648.495895-1-marex@denx.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220213022648.495895-1-marex@denx.de> 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: Robert Foss , Sam Ravnborg , Jagan Teki , dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hi Marek, Thank you for the patch. On Sun, Feb 13, 2022 at 03:26:48AM +0100, Marek Vasut wrote: > In rare cases, the bridge may not start up correctly, which usually > leads to no display output. In case this happens, warn about it in > the kernel log. Do you know what this is caused by ? It's a bit annoying to add a 10+ms delay at start time just to be notified of rare cases. > Signed-off-by: Marek Vasut > Cc: Jagan Teki > Cc: Laurent Pinchart > Cc: Linus Walleij > Cc: Robert Foss > Cc: Sam Ravnborg > Cc: dri-devel@lists.freedesktop.org > --- > drivers/gpu/drm/bridge/ti-sn65dsi83.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi83.c b/drivers/gpu/drm/bridge/ti-sn65dsi83.c > index 19daaddd29a41..1d7c154ea1d79 100644 > --- a/drivers/gpu/drm/bridge/ti-sn65dsi83.c > +++ b/drivers/gpu/drm/bridge/ti-sn65dsi83.c > @@ -488,6 +488,11 @@ static void sn65dsi83_atomic_enable(struct drm_bridge *bridge, > /* Clear all errors that got asserted during initialization. */ > regmap_read(ctx->regmap, REG_IRQ_STAT, &pval); > regmap_write(ctx->regmap, REG_IRQ_STAT, pval); > + > + usleep_range(10000, 12000); > + regmap_read(ctx->regmap, REG_IRQ_STAT, &pval); > + if (pval) > + dev_err(ctx->dev, "Unexpected link status 0x%02x\n", pval); > } > > static void sn65dsi83_atomic_disable(struct drm_bridge *bridge, -- Regards, Laurent Pinchart