From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jassi Brar Date: Thu, 28 Jun 2012 15:30:13 +0000 Subject: Re: [PATCH 3/3] OMAPDSS: HDMI: Cache EDID Message-Id: List-Id: References: <1340805944-28805-1-git-send-email-jaswinder.singh@linaro.org> <1340869729.5037.7.camel@deskari> <1340878461.5037.30.camel@deskari> <1340881815.5037.53.camel@deskari> <4FEC47FA.1040801@linaro.org> <1340896458.5037.131.camel@deskari> In-Reply-To: <1340896458.5037.131.camel@deskari> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Tomi Valkeinen Cc: Andy Green , mythripk@ti.com, linux-omap@vger.kernel.org, linux-fbdev@vger.kernel.org, n-dechesne@ti.com, patches@linaro.org On 28 June 2012 20:44, Tomi Valkeinen wrote: > On Thu, 2012-06-28 at 18:43 +0530, Jassi Brar wrote: > >> A quick reaction of my guts say, we simply enable 5V/HPD_IRQ during >> probe and disable during remove. >> HDMI enable/disable via /sysfs/ and HPD (de)assertion, switch only >> HDMI_PHY on/off. >> The user selecting "Autodetect and Configure" option would then equate >> to "(un)loading" of the HDMI driver. >> Not to mean a trivial job. > > One more thing I realized while thinking about this: > > While it could be argued that the power draw from having the tpd12s015 > always enabled is very small, I think it could matter. If you consider a > phone with HDMI output, it's likely that the phone is locked 99% of the > time. When the phone is locked, there's no need to keep the HDMI HPD > enabled. So this could add to a considerable amount of power wasted, if > the HPD was always enabled. > > At least I can't figure out a reason why one would want the HPD to work > when the phone is locked. Also, I have never used the HDMI output on my > phone, so I'd be glad if it was totally powered off if it gave me more > standby hours =). > Of course, I don't suggest imposing any hard rule here. All I suggest is make it platform dependent and provide a way from user-space too to enable/disable HPD. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jassi Brar Subject: Re: [PATCH 3/3] OMAPDSS: HDMI: Cache EDID Date: Thu, 28 Jun 2012 20:48:13 +0530 Message-ID: References: <1340805944-28805-1-git-send-email-jaswinder.singh@linaro.org> <1340869729.5037.7.camel@deskari> <1340878461.5037.30.camel@deskari> <1340881815.5037.53.camel@deskari> <4FEC47FA.1040801@linaro.org> <1340896458.5037.131.camel@deskari> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Return-path: Received: from mail-lb0-f174.google.com ([209.85.217.174]:62047 "EHLO mail-lb0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751733Ab2F1PSO (ORCPT ); Thu, 28 Jun 2012 11:18:14 -0400 Received: by lbbgm6 with SMTP id gm6so3228327lbb.19 for ; Thu, 28 Jun 2012 08:18:13 -0700 (PDT) In-Reply-To: <1340896458.5037.131.camel@deskari> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Tomi Valkeinen Cc: Andy Green , mythripk@ti.com, linux-omap@vger.kernel.org, linux-fbdev@vger.kernel.org, n-dechesne@ti.com, patches@linaro.org On 28 June 2012 20:44, Tomi Valkeinen wrote: > On Thu, 2012-06-28 at 18:43 +0530, Jassi Brar wrote: > >> A quick reaction of my guts say, we simply enable 5V/HPD_IRQ during >> probe and disable during remove. >> HDMI enable/disable via /sysfs/ and HPD (de)assertion, switch only >> HDMI_PHY on/off. >> The user selecting "Autodetect and Configure" option would then equate >> to "(un)loading" of the HDMI driver. >> Not to mean a trivial job. > > One more thing I realized while thinking about this: > > While it could be argued that the power draw from having the tpd12s015 > always enabled is very small, I think it could matter. If you consider a > phone with HDMI output, it's likely that the phone is locked 99% of the > time. When the phone is locked, there's no need to keep the HDMI HPD > enabled. So this could add to a considerable amount of power wasted, if > the HPD was always enabled. > > At least I can't figure out a reason why one would want the HPD to work > when the phone is locked. Also, I have never used the HDMI output on my > phone, so I'd be glad if it was totally powered off if it gave me more > standby hours =). > Of course, I don't suggest imposing any hard rule here. All I suggest is make it platform dependent and provide a way from user-space too to enable/disable HPD.