From mboxrd@z Thu Jan 1 00:00:00 1970 From: Archit Taneja Subject: Re: [PATCH 1/2] OMAPDSS: use DISPC register to detect context loss Date: Tue, 18 Feb 2014 17:09:19 +0530 Message-ID: <53034667.80603@ti.com> References: <1392366572-31729-1-git-send-email-tomi.valkeinen@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from comal.ext.ti.com ([198.47.26.152]:53272 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751809AbaBRLjn (ORCPT ); Tue, 18 Feb 2014 06:39:43 -0500 In-Reply-To: <1392366572-31729-1-git-send-email-tomi.valkeinen@ti.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Tomi Valkeinen , linux-fbdev@vger.kernel.org, linux-omap@vger.kernel.org Cc: Nishanth Menon On Friday 14 February 2014 01:59 PM, Tomi Valkeinen wrote: > Instead of relying on the OMAP specific > omap_pm_get_dev_context_loss_count() to detect register context loss, we > can achieve the same in a much simpler way by just observing the DISPC > registers. > > We always set DISPC's load mode to LOAD_FRAME_ONLY, which is not the > reset value. Thus we can just observe the load mode to see if we have > lost register context. Nice trick :p Reviewed-by: Archit Taneja Archit > > Signed-off-by: Tomi Valkeinen > --- > drivers/video/omap2/dss/dispc.c | 24 +++++++++++------------- > 1 file changed, 11 insertions(+), 13 deletions(-) > > diff --git a/drivers/video/omap2/dss/dispc.c b/drivers/video/omap2/dss/dispc.c > index bbeb8dd7f108..1659aa912d2b 100644 > --- a/drivers/video/omap2/dss/dispc.c > +++ b/drivers/video/omap2/dss/dispc.c > @@ -100,8 +100,6 @@ static struct { > struct platform_device *pdev; > void __iomem *base; > > - int ctx_loss_cnt; > - > int irq; > > unsigned long core_clk_rate; > @@ -357,29 +355,20 @@ static void dispc_save_context(void) > if (dss_has_feature(FEAT_CORE_CLK_DIV)) > SR(DIVISOR); > > - dispc.ctx_loss_cnt = dss_get_ctx_loss_count(); > dispc.ctx_valid = true; > > - DSSDBG("context saved, ctx_loss_count %d\n", dispc.ctx_loss_cnt); > + DSSDBG("context saved\n"); > } > > static void dispc_restore_context(void) > { > - int i, j, ctx; > + int i, j; > > DSSDBG("dispc_restore_context\n"); > > if (!dispc.ctx_valid) > return; > > - ctx = dss_get_ctx_loss_count(); > - > - if (ctx >= 0 && ctx == dispc.ctx_loss_cnt) > - return; > - > - DSSDBG("ctx_loss_count: saved %d, current %d\n", > - dispc.ctx_loss_cnt, ctx); > - > /*RR(IRQENABLE);*/ > /*RR(CONTROL);*/ > RR(CONFIG); > @@ -3768,6 +3757,15 @@ static int dispc_runtime_suspend(struct device *dev) > > static int dispc_runtime_resume(struct device *dev) > { > + /* > + * The reset value for load mode is 0 (OMAP_DSS_LOAD_CLUT_AND_FRAME) > + * but we always initialize it to 2 (OMAP_DSS_LOAD_FRAME_ONLY) in > + * _omap_dispc_initial_config(). We can thus use it to detect if > + * we have lost register context. > + */ > + if (REG_GET(DISPC_CONFIG, 2, 1) == OMAP_DSS_LOAD_FRAME_ONLY) > + return 0; > + > _omap_dispc_initial_config(); > > dispc_restore_context(); >