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 2470AC38A2D for ; Thu, 27 Oct 2022 08:32:29 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id EB14510E57D; Thu, 27 Oct 2022 08:32:27 +0000 (UTC) Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by gabe.freedesktop.org (Postfix) with ESMTPS id F04DC10E585 for ; Thu, 27 Oct 2022 08:32:24 +0000 (UTC) Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1onyJL-0000ZO-GM; Thu, 27 Oct 2022 10:32:23 +0200 Received: from mfe by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1onyJL-0007Xv-2S; Thu, 27 Oct 2022 10:32:23 +0200 Date: Thu, 27 Oct 2022 10:32:23 +0200 From: Marco Felsch To: Marek Vasut Subject: Re: [PATCH] drm: lcdif: Set and enable FIFO Panic threshold Message-ID: <20221027083223.cwgymey4ar247afe@pengutronix.de> References: <20221026212002.542375-1-marex@denx.de> <20221027081323.luobufjh3n4isiy7@pengutronix.de> <9deaa960-778b-a640-a63e-0da5aaf9b934@denx.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9deaa960-778b-a640-a63e-0da5aaf9b934@denx.de> User-Agent: NeoMutt/20180716 X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: mfe@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: dri-devel@lists.freedesktop.org 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: Peng Fan , Liu Ying , Kieran Bingham , dri-devel@lists.freedesktop.org, Martyn Welch , Laurent Pinchart , Sam Ravnborg Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 22-10-27, Marek Vasut wrote: > On 10/27/22 10:13, Marco Felsch wrote: > > Hi, > > [...] > > > > diff --git a/drivers/gpu/drm/mxsfb/lcdif_kms.c b/drivers/gpu/drm/mxsfb/lcdif_kms.c > > > index a5302006c02cd..aee7babb5fa5c 100644 > > > --- a/drivers/gpu/drm/mxsfb/lcdif_kms.c > > > +++ b/drivers/gpu/drm/mxsfb/lcdif_kms.c > > > @@ -341,6 +341,18 @@ static void lcdif_enable_controller(struct lcdif_drm_private *lcdif) > > > reg = readl(lcdif->base + LCDC_V8_CTRLDESCL0_5); > > > reg |= CTRLDESCL0_5_EN; > > > writel(reg, lcdif->base + LCDC_V8_CTRLDESCL0_5); > > > + > > > + /* Set FIFO Panic watermarks, low 1/3, high 2/3 . */ > > > + writel(FIELD_PREP(PANIC0_THRES_LOW_MASK, 1 * PANIC0_THRES_RANGE / 3) | > > > + FIELD_PREP(PANIC0_THRES_HIGH_MASK, 2 * PANIC0_THRES_RANGE / 3), > > > + lcdif->base + LCDC_V8_PANIC0_THRES); > > > + > > > + /* > > > + * Enable FIFO Panic, this does not generate interrupt, but > > > + * boosts NoC priority based on FIFO Panic watermarks. > > > + */ > > > + writel(INT_ENABLE_D1_PLANE_PANIC_EN, > > > + lcdif->base + LCDC_V8_INT_ENABLE_D1); > > > > Out of curiosity since we have a patch doing the exact same thing but > > didn't saw any improvements. Is there a reason why you enabled it here? > > It seems like the right thing to do here, when enabling the controller. > > > We did this during lcdif_rpm_resume(). But as I said with a 1080P > > display we still saw the flickering, it disappeared first after rising > > the burst-size. > > That's what the NXP downstream driver does too, isn't it ? That seems like > the wrong place to me. Yes, I think so. It's not about the place (if it wrong/correct) it is more about the PANIC mode itself. I'm curios about: 1) Do you still see the flickering with this patch and without the "burst-size increase" patch? 2) Do you still saw flickering after the "burst-size increase" patch applied and without this patch? I had no 4K display therefore I'm asking, but with 1080P we didn't saw any improvements without increasing the burst-size. My assumption was: if the panic mode does work, than I don't have to increase the burst-size. Regards, Marco