From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jagan Teki Subject: Re: [PATCH v3 12/25] drm/sun4i: sun6i_mipi_dsi: Add DSI hblk packet overhead Date: Mon, 29 Oct 2018 19:56:27 +0530 Message-ID: References: <20181026144344.27778-1-jagan@amarulasolutions.com> <20181026144344.27778-13-jagan@amarulasolutions.com> <20181029092227.mdxgvg5aqzh22j72@flea> Reply-To: jagan-dyjBcgdgk7Pe9wHmmfpqLFaTQe2KTcn/@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: Sender: linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org In-Reply-To: <20181029092227.mdxgvg5aqzh22j72@flea> List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , To: Maxime Ripard Cc: Chen-Yu Tsai , Icenowy Zheng , Jernej Skrabec , Vasily Khoruzhick , Rob Herring , Mark Rutland , Catalin Marinas , Will Deacon , David Airlie , dri-devel , Michael Turquette , Stephen Boyd , linux-clk , Michael Trimarchi , linux-arm-kernel , devicetree , linux-kernel , linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org List-Id: dri-devel@lists.freedesktop.org On Mon, Oct 29, 2018 at 2:52 PM Maxime Ripard wrote: > > On Fri, Oct 26, 2018 at 08:13:31PM +0530, Jagan Teki wrote: > > Add 10 bytes packet overhead for hblk where blank is set using > > a blanking packet like (4 bytes + 4 bytes + payload + 2 bytes) > > > > This is according to BSP code from BPI-M64-bsp > > (in drivers/video/sunxi/disp2/disp/de/lowlevel_sun50iw1/de_dsi.c) > > dsi_hblk = (ht-hspw)*dsi_pixel_bits[format]/8-(4+4+2); > > > > So, add 10 bytes packet overhead for DSI hblk. > > > > Tested on 2-lane, 4-lane MIPI-DSI LCD panels. > > > > Signed-off-by: Jagan Teki > > Tested-by: Jagan Teki > > --- > > Changes for v3: > > - new patch > > Changes for v2: > > - none > > > > drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 9 +++++++-- > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > index 596e560263bf..cf42be1f1ba1 100644 > > --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > @@ -461,7 +461,7 @@ static void sun6i_dsi_setup_timings(struct sun6i_dsi *dsi, > > { > > struct mipi_dsi_device *device = dsi->device; > > unsigned int Bpp = mipi_dsi_pixel_format_to_bpp(device->format) / 8; > > - u16 hbp, hfp, hsa, hblk, vblk; > > + u16 hbp, hfp, hsa, hblk_max, hblk, vblk; > > size_t bytes; > > u8 *buffer; > > > > @@ -494,8 +494,13 @@ static void sun6i_dsi_setup_timings(struct sun6i_dsi *dsi, > > > > /* > > * hblk seems to be the line + porches length. > > + * The blank is set using a blanking packet (4 bytes + 4 bytes + > > + * payload + 2 bytes). So minimal size is 10 bytes > > */ > > - hblk = (mode->htotal - (mode->hsync_end - mode->hsync_start)) * Bpp; > > +#define HBLK_PACKET_OVERHEAD 10 > > + hblk_max = (mode->htotal - (mode->hsync_end - mode->hsync_start)) * Bpp; > > + hblk_max -= HBLK_PACKET_OVERHEAD; > > + hblk = max((unsigned int)HBLK_PACKET_OVERHEAD, hblk_max); > > I'd rather use the same convention than the other assignments done > before in that function. Yes, old code did use hsa. but it's added 10 bytes packet head instead of subtracting it. hblk = mode->htotal * Bpp - hsa; => mode->htotal * Bpp - (mode->hsync_end - mode->hsync_start) * Bpp - HSA_PACKET_OVERHEAD); => (mode->htotal - (mode->hsync_end - mode->hsync_start)) * Bpp + HSA_PACKET_OVERHEAD; And it should be (mode->htotal - (mode->hsync_end - mode->hsync_start)) * Bpp - HSA_PACKET_OVERHEAD; This patch is simply doing the same by explicitly adding packet over ahead macro, which again used in hfp.