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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 71543C4727C for ; Tue, 29 Sep 2020 21:11:56 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id D794420757 for ; Tue, 29 Sep 2020 21:11:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D794420757 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 1C43E6E1EC; Tue, 29 Sep 2020 21:11:55 +0000 (UTC) Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by gabe.freedesktop.org (Postfix) with ESMTPS id A77C26E1EC; Tue, 29 Sep 2020 21:11:53 +0000 (UTC) IronPort-SDR: vkgce8qWYsediiJesM3dtGqedF0rR+0wdI7w5ktGlH9k8Y+N1EycWlst3EVuwwyaYixBrG13VG b7plSznmvKgQ== X-IronPort-AV: E=McAfee;i="6000,8403,9759"; a="247021694" X-IronPort-AV: E=Sophos;i="5.77,319,1596524400"; d="scan'208";a="247021694" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Sep 2020 14:11:53 -0700 IronPort-SDR: jWa+6osF7t7buvmXJEmL1EyMaCgRd+lglNeUdQMrDEQyVZlBI2JyXo5pJvp00X4S0+cE3JLYy6 j0JSPa+LTMow== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,319,1596524400"; d="scan'208";a="345408105" Received: from stinkbox.fi.intel.com (HELO stinkbox) ([10.237.72.174]) by fmsmga002.fm.intel.com with SMTP; 29 Sep 2020 14:11:48 -0700 Received: by stinkbox (sSMTP sendmail emulation); Wed, 30 Sep 2020 00:11:48 +0300 Date: Wed, 30 Sep 2020 00:11:48 +0300 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Matt Roper Subject: Re: [PATCH v2] drm/i915/edp/jsl: Update vswing table for HBR and HBR2 Message-ID: <20200929211148.GJ6112@intel.com> References: <20200929121127.254086-1-tejaskumarx.surendrakumar.upadhyay@intel.com> <20200929200201.GH6112@intel.com> <20200929203022.GI6112@intel.com> <20200929210144.GA2214475@mdroper-desk1.amr.corp.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200929210144.GA2214475@mdroper-desk1.amr.corp.intel.com> X-Patchwork-Hint: comment User-Agent: Mutt/1.10.1 (2018-07-13) 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: "Pandey, Hariom" , "Ausmus, James" , "intel-gfx@lists.freedesktop.org" , "De Marchi, Lucas" , "dri-devel@lists.freedesktop.org" , "Souza, Jose" , "Surendrakumar Upadhyay, TejaskumarX" Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Tue, Sep 29, 2020 at 02:01:44PM -0700, Matt Roper wrote: > On Tue, Sep 29, 2020 at 11:30:22PM +0300, Ville Syrj=E4l=E4 wrote: > > On Tue, Sep 29, 2020 at 08:20:22PM +0000, Souza, Jose wrote: > > > On Tue, 2020-09-29 at 23:02 +0300, Ville Syrj=E4l=E4 wrote: > > > > On Tue, Sep 29, 2020 at 07:33:45PM +0000, Souza, Jose wrote: > > > > > On Tue, 2020-09-29 at 17:41 +0530, Tejas Upadhyay wrote: > > > > > > JSL has update in vswing table for eDP > > > > > = > > > > > Would be nice to mention in the commit description why PCH is bei= ng used, that would avoid Ville's question. > > > > = > > > > If the thing has nothing to do PCH then it should not use the PCH t= ype > > > > for the the check. Instead we should just do the EHL/JSL split. > > > = > > > In the first version Matt Roper suggested to use PCH to differentiate= between EHL and JSL, Jani also agreed with this solution.This 2 PCHs can o= nly be > > > associate with EHL and JSL respectively, so no downsides here. > > = > > The downside is that the code makes no sense on the first glance. > > It's going to generate a "wtf?" exception in the brain and require > > me to take a second look to figure what is going on. Exception > > handling is expensive and shouldn't be needed in cases where it's > > trivial to make the code 100% obvious. > = > The bspec documents EHL and JSL as being the same platform and identical > in all programming since they are literally the same display IP; this > vswing table is the one and only place where the two are treated in a > distinct manner for reasons that lie outside the display controller. If > you had to stop and take a closer look at the code here, that's a > probably a good thing since in general there should generally never be a > difference in the behavior between the two. Adding an additional > clarifying comment is probably in order too since this is a very > exceptional special case. > = > If we deviate from the bspec's guidance and try to split IS_ELKHARTLAKE > and IS_JASPERLAKE across the whole driver, that's going to be a lot more > pain to maintain down the road since we'll almost certainly have cases > where someone silently leaves one or the other off a condition and gets > unexepcted behavior. I could see arguments for using a SUBPLATFORM here > like we do for TGL_U vs TGL_Y, but even that seems like overkill if we > already have a clear way to distinguish the two cases (PCH pairing) and > can just leave a clarifying comment. That fixed PCH pairing is totally undocumented AFAICS. And vswing has nothing to do with the south display, so the wtf will still happen. Comment or no comment. -- = Ville Syrj=E4l=E4 Intel _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel 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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DE313C4727D for ; Tue, 29 Sep 2020 21:11:58 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 78A1420757 for ; Tue, 29 Sep 2020 21:11:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 78A1420757 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 809386E1F3; Tue, 29 Sep 2020 21:11:55 +0000 (UTC) Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by gabe.freedesktop.org (Postfix) with ESMTPS id A77C26E1EC; Tue, 29 Sep 2020 21:11:53 +0000 (UTC) IronPort-SDR: vkgce8qWYsediiJesM3dtGqedF0rR+0wdI7w5ktGlH9k8Y+N1EycWlst3EVuwwyaYixBrG13VG b7plSznmvKgQ== X-IronPort-AV: E=McAfee;i="6000,8403,9759"; a="247021694" X-IronPort-AV: E=Sophos;i="5.77,319,1596524400"; d="scan'208";a="247021694" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Sep 2020 14:11:53 -0700 IronPort-SDR: jWa+6osF7t7buvmXJEmL1EyMaCgRd+lglNeUdQMrDEQyVZlBI2JyXo5pJvp00X4S0+cE3JLYy6 j0JSPa+LTMow== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,319,1596524400"; d="scan'208";a="345408105" Received: from stinkbox.fi.intel.com (HELO stinkbox) ([10.237.72.174]) by fmsmga002.fm.intel.com with SMTP; 29 Sep 2020 14:11:48 -0700 Received: by stinkbox (sSMTP sendmail emulation); Wed, 30 Sep 2020 00:11:48 +0300 Date: Wed, 30 Sep 2020 00:11:48 +0300 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Matt Roper Message-ID: <20200929211148.GJ6112@intel.com> References: <20200929121127.254086-1-tejaskumarx.surendrakumar.upadhyay@intel.com> <20200929200201.GH6112@intel.com> <20200929203022.GI6112@intel.com> <20200929210144.GA2214475@mdroper-desk1.amr.corp.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200929210144.GA2214475@mdroper-desk1.amr.corp.intel.com> X-Patchwork-Hint: comment User-Agent: Mutt/1.10.1 (2018-07-13) Subject: Re: [Intel-gfx] [PATCH v2] drm/i915/edp/jsl: Update vswing table for HBR and HBR2 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: , Cc: "Pandey, Hariom" , "intel-gfx@lists.freedesktop.org" , "De Marchi, Lucas" , "dri-devel@lists.freedesktop.org" Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Tue, Sep 29, 2020 at 02:01:44PM -0700, Matt Roper wrote: > On Tue, Sep 29, 2020 at 11:30:22PM +0300, Ville Syrj=E4l=E4 wrote: > > On Tue, Sep 29, 2020 at 08:20:22PM +0000, Souza, Jose wrote: > > > On Tue, 2020-09-29 at 23:02 +0300, Ville Syrj=E4l=E4 wrote: > > > > On Tue, Sep 29, 2020 at 07:33:45PM +0000, Souza, Jose wrote: > > > > > On Tue, 2020-09-29 at 17:41 +0530, Tejas Upadhyay wrote: > > > > > > JSL has update in vswing table for eDP > > > > > = > > > > > Would be nice to mention in the commit description why PCH is bei= ng used, that would avoid Ville's question. > > > > = > > > > If the thing has nothing to do PCH then it should not use the PCH t= ype > > > > for the the check. Instead we should just do the EHL/JSL split. > > > = > > > In the first version Matt Roper suggested to use PCH to differentiate= between EHL and JSL, Jani also agreed with this solution.This 2 PCHs can o= nly be > > > associate with EHL and JSL respectively, so no downsides here. > > = > > The downside is that the code makes no sense on the first glance. > > It's going to generate a "wtf?" exception in the brain and require > > me to take a second look to figure what is going on. Exception > > handling is expensive and shouldn't be needed in cases where it's > > trivial to make the code 100% obvious. > = > The bspec documents EHL and JSL as being the same platform and identical > in all programming since they are literally the same display IP; this > vswing table is the one and only place where the two are treated in a > distinct manner for reasons that lie outside the display controller. If > you had to stop and take a closer look at the code here, that's a > probably a good thing since in general there should generally never be a > difference in the behavior between the two. Adding an additional > clarifying comment is probably in order too since this is a very > exceptional special case. > = > If we deviate from the bspec's guidance and try to split IS_ELKHARTLAKE > and IS_JASPERLAKE across the whole driver, that's going to be a lot more > pain to maintain down the road since we'll almost certainly have cases > where someone silently leaves one or the other off a condition and gets > unexepcted behavior. I could see arguments for using a SUBPLATFORM here > like we do for TGL_U vs TGL_Y, but even that seems like overkill if we > already have a clear way to distinguish the two cases (PCH pairing) and > can just leave a clarifying comment. That fixed PCH pairing is totally undocumented AFAICS. And vswing has nothing to do with the south display, so the wtf will still happen. Comment or no comment. -- = Ville Syrj=E4l=E4 Intel _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx