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 CA093CCF9E3 for ; Thu, 30 Oct 2025 11:50:07 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 03B9910E145; Thu, 30 Oct 2025 11:50:07 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="SJ4psI5M"; dkim-atps=neutral Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by gabe.freedesktop.org (Postfix) with ESMTPS id BC96D10E145 for ; Thu, 30 Oct 2025 11:50:05 +0000 (UTC) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id E88FF60459; Thu, 30 Oct 2025 11:50:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9D596C4CEF1; Thu, 30 Oct 2025 11:50:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761825004; bh=moMPcJsHoh+D5tFeCvN/Eh1IJ6XaSFfSJQcEu0+Vvog=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=SJ4psI5MuXqxCO245p9pGERpCQi5pHOVlT7DSYUE/R4AZa/VnB170AnM6D47963zL H7ilQkhTy9xoyz/JbV1n9FQzp2hjWkNHqtj1iq8zRYPg+BIefMMJetoKH80QG1JmnO JT+xhsXNTO53e95Gq/dgJyvDnQ9ICtITcXrSi5WiIfRBykNaMFHlUTWFqbKizHDtd2 TAD1nYg1xr1HDhsI1Zvt9UTUGTWGoU1wvjHAlFGpAVPuK47N3Z20abhOA9xA28jVVK O6Bmr69H7I5bVwYirMdP7n7ALFwT9pMEWTetRVwDQUnd4s1k5MflOTV+ZtM2AX9qC4 LTOXGvLmfxt6A== Date: Thu, 30 Oct 2025 11:51:07 +0000 From: Daniel Thompson To: Michael Grzeschik Cc: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= , Lee Jones , Jingoo Han , Helge Deller , Pengutronix , linux-pwm@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] backlight: pwm_bl: apply the initial backlight state with sane defaults Message-ID: References: <20250731-blpwm-v1-1-0171fd31bff9@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250731-blpwm-v1-1-0171fd31bff9@pengutronix.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: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Thu, Jul 31, 2025 at 10:47:18AM +0200, Michael Grzeschik wrote: > Currently when calling pwm_apply_might_sleep in the probe routine > the pwm will be configured with an not fully defined state. > > The duty_cycle is not yet set in that moment. There is a final > backlight_update_status call that will have a properly setup state. > However this change in the backlight can create a short flicker if the > backlight was already preinitialised. > > We fix the flicker by moving the pwm_apply after the default duty_cycle > can be calculated. > > Signed-off-by: Michael Grzeschik Reviewed-by: Daniel Thompson (RISCstar) Daniel.