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 320E4D767D8 for ; Thu, 31 Oct 2024 14:56:04 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id CA85910E406; Thu, 31 Oct 2024 14:56:03 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="kRCMQuy6"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.18]) by gabe.freedesktop.org (Postfix) with ESMTPS id BB2FB10E406 for ; Thu, 31 Oct 2024 14:56:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1730386563; x=1761922563; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=TYoKocrXmoWPpEwvF06eZ4iXoYwvkrUkJWfUt4bnotg=; b=kRCMQuy6YRajT1XaY6rfWj38OrT8brTT6mfCEtU/CYZTVPzSAI3rYEJv IPl556mRPID710JzqvRXED/qosHI3bFCLibR01kLmdUAJ15QndiJ/UXy9 hv4TjCvCVLJGLVE1jgyvc/aEpPdOoC2BZVJlKEG8wuXKi304FN2xoqqcW hUj4Y4uquR2wtyS8J3NFxExe+KiGtyjwWfYpsK1UetbFswUC+e6OIUJxB /HZeiofRT2lrdwD2zwZ3B6qnhpzFBP9m8oK8Ek5H+MsddmAcfTtiuaaY4 CF9vSMqDsWN8YRq8zWb1Sqo1fq5YFrNejbuIHps/NgBHWW+CentSLxbU6 A==; X-CSE-ConnectionGUID: f03PhFrlQ9uQGadA+56XEQ== X-CSE-MsgGUID: v0mzbID8SF2bDOT3Mj5psQ== X-IronPort-AV: E=McAfee;i="6700,10204,11242"; a="29546656" X-IronPort-AV: E=Sophos;i="6.11,247,1725346800"; d="scan'208";a="29546656" Received: from orviesa002.jf.intel.com ([10.64.159.142]) by fmvoesa112.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Oct 2024 07:55:23 -0700 X-CSE-ConnectionGUID: A9qKMayPQ9KjAW5BzZdOIQ== X-CSE-MsgGUID: OqLxCR5FSwOCbeBszRSn9g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.11,247,1725346800"; d="scan'208";a="113433104" Received: from black.fi.intel.com ([10.237.72.28]) by orviesa002.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Oct 2024 07:55:21 -0700 Date: Thu, 31 Oct 2024 16:55:18 +0200 From: Raag Jadav To: "Kahola, Mika" Cc: "intel-gfx@lists.freedesktop.org" , "Sousa, Gustavo" , "jani.nikula@linux.intel.com" Subject: Re: [PATCH v3 0/2] drm/i915/display: Power request asserting/deasserting Message-ID: References: <20241031114027.225217-1-mika.kahola@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Thu, Oct 31, 2024 at 07:58:19PM +0530, Kahola, Mika wrote: > > -----Original Message----- > > From: Jadav, Raag > > Sent: Thursday, 31 October 2024 14.59 > > To: Kahola, Mika > > Cc: intel-gfx@lists.freedesktop.org; Sousa, Gustavo ; > > jani.nikula@linux.intel.com > > Subject: Re: [PATCH v3 0/2] drm/i915/display: Power request > > asserting/deasserting > > > > On Thu, Oct 31, 2024 at 01:40:25PM +0200, Mika Kahola wrote: > > > There is a HW issue that arises when there are race conditions between > > > TCSS entering/exiting TC7 or TC10 states while the driver is > > > asserting/deasserting TCSS power request. As a workaround, Display > > > driver will implement a mailbox sequence to ensure that the TCSS is in > > > TC0 when TCSS power request is asserted/deasserted. > > > > > > The sequence is the following > > > > > > 1. Read mailbox command status and wait until run/busy bit is > > > clear > > > 2. Write mailbox data value '1' for power request asserting > > > and '0' for power request deasserting 3. Write mailbox command > > > run/busy bit and command value with 0x1 4. Read mailbox command and > > > wait until run/busy bit is clear > > > before continuing power request. > > > > > > while at it, let's start using struct intel_display instead of struct > > > drm_i915_private as well. > > > > Perhaps this needs to be its own patch since it's unrelated to the series. > > There was a request from Jani to start using intel_display instead of > drm_i915_private also with the calling function. So this is perhaps > remotely related to this WA I included this here. Yes, he has a series WIP for it. Perhaps worth collaborating. Raag