Hi Maxime, On Tue, Dec 11, 2018 at 10:30 PM Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx> wrote: > > On Tue, Dec 11, 2018 at 10:19 PM Maxime Ripard > <maxime.ripard@xxxxxxxxxxx> wrote: > > > > On Mon, Dec 10, 2018 at 09:47:19PM +0530, Jagan Teki wrote: > > > 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@xxxxxxxxxxxxxxxxxxxx> > > > > 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. > > > > So, just like I asked in your v4, twice, > > > > http://lists.infradead.org/pipermail/linux-arm-kernel/2018-November/615339.html > > I don't know how can I comment here. Not quite clearly understand your > setup, because I have verified 3 different panels from different > vendors one with 2-lane, another with 4-lane and one with video format > and another one is burstmode format. I even verified with the clock > rate and register details. > > Please suggest me, what can look further on this. >From the BSP point-of-view I couldn't find have any difference in start_delay computation between A64, and A33[1]. In fact the driver initialization code is same, here is A64 dsi driver[2]. 1) The only difference that I observe is dsi_gen_wr in BSP [3], the A33 is right shifting message tx length to 0, 8 for first and next packet where as A64 did the same by adding +1 before. Please try to check that If your panel is using long write. and 2) Also every dsi transaction in A33 occupy some delay code in dsi_gen_wr[4], please check the same. and 3) Also If possible please check your panel timings or initialization sequence, because I don't have any panel with A33. 4) other than these I have didn't notice any differences atleast from my knowledge, Please suggest me where can I look further. [1] https://github.com/BPI-SINOVOIP/BPI-M2M-bsp/blob/master/linux-sunxi/drivers/video/sunxi/disp/de/lowlevel_sun8iw5/de_dsi.c#L813 [2] https://github.com/BPI-SINOVOIP/BPI-M64-bsp/blob/master/linux-sunxi/drivers/video/sunxi/disp2/disp/de/lowlevel_sun50iw1/de_dsi.c [3] https://github.com/BPI-SINOVOIP/BPI-M2M-bsp/blob/master/linux-sunxi/drivers/video/sunxi/disp/de/lowlevel_sun8iw5/de_dsi.c#L402 [4] https://github.com/BPI-SINOVOIP/BPI-M2M-bsp/blob/master/linux-sunxi/drivers/video/sunxi/disp/de/lowlevel_sun8iw5/de_dsi.c#L378 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
