From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Subject: Re: [PATCH v2 01/12] drm/sun4i: sun6i_mipi_dsi: Compute burst mode loop N1 instruction delay Date: Tue, 20 Nov 2018 16:58:26 +0100 Message-ID: <20181120155826.j5rja22jnxpkmjrs@flea> References: <20181116163916.29621-1-jagan@amarulasolutions.com> <20181116163916.29621-2-jagan@amarulasolutions.com> <20181119082707.kbsw2gyntxxbh6no@flea> <20181120132357.xge6gkurjjjvwi2i@flea> Reply-To: maxime.ripard-LDxbnhwyfcJBDgjK7y7TUQ@public.gmane.org Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="q3rnoerzhd6vdmpz" Return-path: Sender: linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org Content-Disposition: inline In-Reply-To: List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , To: Jagan Teki Cc: Maarten Lankhorst , Sean Paul , David Airlie , Rob Herring , Chen-Yu Tsai , Icenowy Zheng , Jernej Skrabec , Vasily Khoruzhick , Thierry Reding , Mark Rutland , dri-devel , devicetree , linux-kernel , linux-arm-kernel , Michael Trimarchi , TL Lim , linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org, linux-amarula-dyjBcgdgk7Pe9wHmmfpqLFaTQe2KTcn/@public.gmane.org List-Id: devicetree@vger.kernel.org --q3rnoerzhd6vdmpz Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline On Tue, Nov 20, 2018 at 07:06:30PM +0530, Jagan Teki wrote: > On Tue, Nov 20, 2018 at 6:53 PM Maxime Ripard wrote: > > > > On Mon, Nov 19, 2018 at 04:28:29PM +0530, Jagan Teki wrote: > > > On Mon, Nov 19, 2018 at 1:57 PM Maxime Ripard wrote: > > > > > > > > On Fri, Nov 16, 2018 at 10:09:05PM +0530, Jagan Teki wrote: > > > > > Loop N1 instruction delay for burst mode lcd panel are > > > > > computed as per BSP code. > > > > > > > > > > Reference code is available in BSP (from linux-sunxi > > > > > drivers/video/sunxi/disp2/disp/de/lowlevel_sun50iw1/de_dsi.c) > > > > > > > > > > dsi_dev[sel]->dsi_inst_loop_num.bits.loop_n1= > > > > > (panel->lcd_ht-panel->lcd_x)*(150)/(panel->lcd_dclk_freq*8) - 50; > > > > > => (((mode->htotal - mode->hdisplay) * 150) / > > > > > ((mode->clock / 1000) * 8)) - 50; > > > > > > > > > > So use the similar computation for loop N1 delay. > > > > > > > > > > Signed-off-by: Jagan Teki > > > > > > > > *why* are you doing this? What is it fixing? on which devices? > > > > > > You mentioned the separate function to compute the delay for all modes > > > [1], ie what I did. did I missing anything? > > > > You're missing that you are never explaining why that patch is needed > > in the first place. Or answering the question I asked a couple of > > lines above. > > OK. > > The instruction delay varies between video and burst mode. for burst > mode panels it is computed based on the panel clock along with > horizontal sync+porch timings. You're still stating a fact. What issue, that you experienced, are you trying to solve here? Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com --q3rnoerzhd6vdmpz--