Re: [PATCH v5 07/17] drm/sun4i: sun6i_mipi_dsi: Refactor vertical video start delay
From: Maxime Ripard <hidden>
Date: 2019-01-12 16:43:34
Also in:
dri-devel, linux-clk, lkml
On Wed, Jan 09, 2019 at 06:57:57PM +0530, Jagan Teki wrote:
On Tue, Jan 8, 2019 at 2:28 PM Maxime Ripard [off-list ref] wrote:quoted
On Mon, Jan 07, 2019 at 08:48:21PM +0530, Jagan Teki wrote:quoted
On Mon, Jan 7, 2019 at 7:42 PM Maxime Ripard [off-list ref] wrote:quoted
On Fri, Dec 21, 2018 at 02:26:11AM +0530, Jagan Teki wrote:quoted
On Tue, Dec 11, 2018 at 10:19 PM Maxime Ripard [off-list ref] wrote:quoted
On Mon, Dec 10, 2018 at 09:47:19PM +0530, Jagan Teki wrote:quoted
Video start delay can be computed by subtracting total vertical timing with front porch timing and with adding 1 delay line for TCON. BSP code form BPI-M64-bsp is computing video start delay as (from linux-sunxi/ drivers/video/sunxi/disp2/disp/de/lowlevel_sun50iw1/de_dsi.c) u32 vfp = panel->lcd_vt - panel->lcd_y - panel->lcd_vbp; => (panel->lcd_vt) - panel->lcd_y - (panel->lcd_vbp) => (timmings->ver_front_porch + panel->lcd_vbp + panel->lcd_y) - panel->lcd_y - (panel->lcd_vbp) => timmings->ver_front_porch + panel->lcd_vbp + panel->lcd_y - panel->lcd_y - panel->lcd_vbp => timmings->ver_front_porch So, update the start delay computation accordingly. Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>Even though it's a bit better now on my A33 board and I don't have the white stripes on the bottom of the display, there's still some flickering with your patches applied. Bisecting it seems to point at that patch, but reverting it doesn't make the issue go away, so it's not really clear which one exactly is at fault.Is reverting this patch, work fine or not?As I was saying, it doesn't.quoted
This patch is trying to make use of front porch instead of existing back porch to compute the delay. Since we revert the VBP fix patch[1] to assume VBP as VFP value look like your setup would also require to revert this change. But as per BSP or drm_mode details all of my displays even work with and w/o reverting these two.Again, I cannot help you without the datasheet for the panels you're trying to submit.The panel bound with Sitronix ST7701 IC http://www.startek-lcd.com/res/starteklcd/pdres/201705/20170512144242904.pdfIt's the controller, not the panelAs I said before, the datasheet of that panel doesn't have any information except electrical characteristics and used IC which is ST7701. I have one more panel, which is from Bananapi, S070WV20-CT16 ICN621 please find the attachment for the same. Here is some more details of the same. https://github.com/yesnoandor/x300/blob/master/kernel/arch/arm/boot/dts/erobbing/x300/x300.dtsi#L81 https://github.com/wxzed/Raspberry_5MIPI_Display/blob/master/I2C_Slave/USER/main.c#L15 https://github.com/eliot-shao/qcom/blob/master/icn6211_cxn0102/kernel/drivers/video/msm/mdss/mdss_i2c_interface.c#L152 matches timings for https://github.com/eliot-shao/qcom/blob/master/icn6211_cxn0102/kernel/arch/arm/boot/dts/qcom/dsi-mipi-2-rgb_1280p_video.dtsi#L20 https://github.com/zestroly/micromat/blob/master/test/raspberry/ICN6211.cpp#L169
Where did you get the timings from then? Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel