From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grygorii Strashko Subject: Re: Multiple issues with omap4 panda es in linux next Date: Mon, 22 Apr 2013 15:21:28 +0300 Message-ID: <51752B48.50700@ti.com> References: <20130419171318.GK10155@atomide.com> <5174FE16.6080307@ti.com> <51750FF8.6000401@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from devils.ext.ti.com ([198.47.26.153]:59142 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752818Ab3DVMWZ (ORCPT ); Mon, 22 Apr 2013 08:22:25 -0400 In-Reply-To: <51750FF8.6000401@ti.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Tomi Valkeinen Cc: Tony Lindgren , linux-omap@vger.kernel.org, Felipe Balbi , Luciano Coelho , Roger Quadros , linux-arm-kernel@lists.infradead.org, Santosh Shilimkar , Kishon Vijay Abraham I , Ravi Babu , Ruslan Bilovol On 04/22/2013 01:24 PM, Tomi Valkeinen wrote: > On 2013-04-22 12:08, Tomi Valkeinen wrote: >> On 2013-04-19 20:13, Tony Lindgren wrote: >> >>> 3. DSS fails with DT booting >>> >>> Works with legacy booting but fails with DT. I'm almost certain >>> the DT booting was working last week or so? >>> >>> This is what I now get with DT booting: >>> >>> omapdss DSI error: can't get VDDS_DSI regulator >>> omapdss HDMI error: can't get VDDA_HDMI_DAC regulator >>> omapdss HDMI error: device hdmi init failed: -517 >>> omapdss CORE error: driver probe failed: -22 >>> ... >> I think this is the issue Christoph Fritz reported earlier, DSS is being >> initialized before TWL, and thus DSS doesn't find the regulators. >> >> The proper fix is of course to make DSS support EPROBE_DEFER, but that's >> easier said than done. I'll have a look if I can get it working enough >> to fix this issue. > Yes, it seems delayed regulator initialization brought up this issue. > > I hacked DSI driver of omapdss and Taal panel driver to somewhat work > with EPROBE_DEFER. But then the issue was with omapfb. > > omapfb is currently set to start at late_initcall, so that omapdss and > panels are loaded before omapfb. But even that's not late enough to get > the regulators for omapdss. It seems the regulators get also initialized > at the late_initcall level. Changing omapfb to late_initcall_sync was > late enough to get things working. > > Again, making omapdss, panel drivers and omapfb support EPROBE_DEFER and > dynamic panel driver insertion is the proper fix, but it's a big job, > and there are "interesting" issues with it (like how to know if a panel > device will ever get a driver loaded). > > But is there something wrong with the TWL and regulators? late_initcall > sounds rather late for such a core resource. Even if all drivers > supported EPROBE_DEFER, won't it cause extra delays in the boot as > drivers are getting probed multiple times? > > As for fixing the DSS problem for 3.10, I don't have any ideas except > pure hacks. I'll continue studying this. Hi Tomi, twl is not initialized because of I2C, I2C is not initialized because of pinctrl-single, pinctrl-single is initialized at mudule/device init time. So, most everything will be shifted at late_initcall time. Hack that sequence is here - https://patchwork.kernel.org/patch/2444501/ > > Tomi > >