From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.14]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B601E4A3F26; Mon, 19 Oct 2026 09:58:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.14 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792403935; cv=none; b=HVzmSkfbx3KEnp5tUo/06HgdoHPi+NNBGxO8OFh+L1PbCBcYHZjkeo7E7zXmO/i9iIYkgkyju9XNK/PeDEIIceWRcM1Gah352gVFPTdPWJs6G/KfRoZz/EW1j9vYFL2tgYi7J88nHpvg929gCidSyzck/iLpdBBCXDiuXEKvBV8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792403935; c=relaxed/simple; bh=FCF+CStTLQKo129wcMJjO9zPQelHyhJZb6dyEUr5q7k=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ElLhOWQFNUxXaVY7faBRKIz9jwJCzoOywnY26UiSAvYIk79tUww9jMX9v99ia8mstYB+3Hy9P39uftxgNSR+vcD0ZH1l14GYVJf2G32nM11hDhSMuo//Nzpa+ogfdWKETX08UU3LfoSddANDhZmOYNAQoZijiNCErvTE359rXnk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=e4nwNIKa; arc=none smtp.client-ip=192.198.163.14 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="e4nwNIKa" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1792403934; x=1823939934; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=FCF+CStTLQKo129wcMJjO9zPQelHyhJZb6dyEUr5q7k=; b=e4nwNIKaUVbDN50Wdgdp0BrJANLCNqBsGbFd1NAKEl9Xv51svADuVnCB XQGDbPsZNsouM0xTMZOxJW+vK35MxaWif9KSH7vgbIw9RMqOJMM/sjeJF 9yYhR8Wwoe7a79aeDD3oXjQ1WRzuIVzKSF1lfxW6TqNkt0OqxRZep5wlF SVHRiZY/uck9smPu5V3pRfkGhNFRr/vJ0GZsJMfO3d84LNsbXCdb/qP1I 9Lf6b1HeDV/Mjg/9g6nrWA5YhTU0SxzfWqQZRN4h1I79NC7BTu/zGQ52J uQkOYO4U+bs5pl8Pj9LsP7FiZXtzf2JDEfyJyz2hHI4S1kWzHsNMVjQwM w==; X-CSE-ConnectionGUID: BonMpdgZRhmG0kTYrwAXgw== X-CSE-MsgGUID: ICGuKOeAQLStyCo3zpo/4Q== X-IronPort-AV: E=McAfee;i="6800,10657,11939"; a="1103095" X-IronPort-AV: E=Sophos;i="6.27,167,1787036400"; d="scan'208";a="1103095" Received: from fmviesa013.fm.intel.com ([10.60.135.153]) by fmvoesa108.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Oct 2026 02:58:54 -0700 X-CSE-ConnectionGUID: 7uDefMOhT1e07ff2UgJhDQ== X-CSE-MsgGUID: oZGsXOw8Qty5qXALoo+IuA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.27,167,1787036400"; d="scan'208";a="4277332" Received: from pgcooper-mobl3.ger.corp.intel.com (HELO localhost) ([10.245.245.209]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Oct 2026 02:58:51 -0700 Date: Mon, 19 Oct 2026 12:58:48 +0300 From: Andy Shevchenko To: mwwa919@gmail.com Cc: Jani Nikula , Rodrigo Vivi , intel-gfx@lists.freedesktop.org, Joonas Lahtinen , Tvrtko Ursulin , David Airlie , Simona Vetter , Hans de Goede , intel-xe@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] drm/i915/dsi: Use owned panel/backlight GPIOs in VLV MIPI sequences Message-ID: References: <20261018-vlv-dsi-owned-gpios-v1-1-3ca18bcda670@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261018-vlv-dsi-owned-gpios-v1-1-3ca18bcda670@gmail.com> Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo On Sun, Oct 18, 2026 at 04:12:40PM -0400, Mike Anderson via B4 Relay wrote: > On VLV with PPS_BLC_SOC, intel_dsi_vbt_gpio_init() requests the > backlight and panel enable GPIOs (INT33FC:01 pins 10 and 11) for i915 > itself. Since commit 8241b55f1ded ("drm/i915/dsi: Replace poking of VLV > GPIOs behind the driver's back") the GPIO elements of the VBT MIPI > sequences also request their pin through gpiolib, so when a sequence > toggles one of these two pins the request fails and the toggle is > dropped: > > i915 0000:00:02.0: [drm] *ERROR* GPIO index 10 request failed (-EBUSY) > > Before that commit the pad registers were written directly, so the > sequences could still drive the pins i915 owned. > > The Toshiba Encore 2 WT8-B (Bay Trail, DSI panel) uses pin 10 as the > panel reset line: MIPI_SEQ_ASSERT_RESET drives it low and > MIPI_SEQ_DEASSERT_RESET pulses it high-low-high. With every toggle > failing, the panel is never reset after i915 sends MIPI_SEQ_DISPLAY_OFF > during takeover and stays black, even though the backlight PWM and both > enable GPIOs read back as on. The tablet only has a usable display > with nomodeset. > > When a VLV MIPI sequence targets pin 10 or 11 and i915 holds the > corresponding descriptor, set it through that descriptor instead of > requesting the pin a second time. Ah, nice, this should be solved via using reset-gpio, which is exactly fixed for the reset shared lines case. -- With Best Regards, Andy Shevchenko