On Mon, Oct 01, 2018 at 01:39:17PM +0530, Jagan Teki wrote: > On Saturday 29 September 2018 07:23 PM, Maxime Ripard wrote: > > On Thu, Sep 27, 2018 at 09:50:34PM +0530, Jagan Teki wrote: > > > On Thu, Sep 27, 2018 at 8:51 PM Maxime Ripard <maxime.ripard@xxxxxxxxxxx> wrote: > > > > > > > > On Thu, Sep 27, 2018 at 05:18:44PM +0530, Jagan Teki wrote: > > > > > According to horizontal and vertical timings are defined > > > > > per the diagram from include/drm/drm_modes.h > > > > > > > > > > Back porch = [hv]total - [hv]sync_end > > > > > > > > > > So, update SUN6I_DSI_BASIC_SIZE0_VBP calculation as > > > > > mode->vtotal - mode->vsync_end > > > > > > > > > > Signed-off-by: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx> > > > > > --- > > > > > drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 4 ++-- > > > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > > > > > diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > > > > index 1c7e42015645..599284971ab6 100644 > > > > > --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > > > > +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > > > > @@ -526,8 +526,8 @@ static void sun6i_dsi_setup_timings(struct sun6i_dsi *dsi, > > > > > regmap_write(dsi->regs, SUN6I_DSI_BASIC_SIZE0_REG, > > > > > SUN6I_DSI_BASIC_SIZE0_VSA(mode->vsync_end - > > > > > mode->vsync_start) | > > > > > - SUN6I_DSI_BASIC_SIZE0_VBP(mode->vsync_start - > > > > > - mode->vdisplay)); > > > > > + SUN6I_DSI_BASIC_SIZE0_VBP(mode->vtotal - > > > > > + mode->vsync_end)); > > > > > > > > Is it purely theoretical, or did you find some source that back that? > > > > > > VSA is done as per that, sync_end - sync start would give sync time. > > > > That's a different register though. > > > > > VBP also done in BPI-M64-bsp[1] which results back porch existing code > > > results fron porch. > > > > > > [1] https://github.com/BPI-SINOVOIP/BPI-M64-bsp/blob/master/linux-sunxi/drivers/video/sunxi/disp2/disp/de/lowlevel_sun50iw1/de_dsi.c#L955 > > > > That code does back porch - sync length. Such a calculation doesn't > > make much sense as is, but you're saying that it results in the front > > porch. Again, what makes you say that? > > No what code shows is not a real back porch value used for drm it's panel > back porch value which is a DTS property in BSP. > (I made wrong comment on previous mail as front porch, sorry) > > here is the real code > > from drivers/video/sunxi/disp2/disp/de/disp_lcd.c > timmings->ver_sync_time= panel_info->lcd_vspw; > timmings->ver_back_porch= panel_info->lcd_vbp-panel_info->lcd_vspw; > > > u32 vbp = panel->lcd_vbp; > u32 vspw = panel->lcd_vspw; > dsi_dev[sel]->dsi_basic_size0.bits.vbp = vbp-vspw; > > So, > > dsi_dev[sel]->dsi_basic_size0.bits.vbp = panel->lcd_vbp - panel->lcd_vspw; > > => timmings->ver_back_porch + panel_info->lcd_vspw - panel_info->lcd_vspw > => timmings->ver_back_porch > => mode->vtotal - mode->end > > VSA, which a proper value. > > dsi_dev[sel]->dsi_basic_size0.bits.vsa = vspw; > => panel_info->lcd_vspw; > => timmings->ver_sync_time > => mode->vsync_end - mode->vsync_start Then please write that in your commit log. Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
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