On Sun, Mar 03, 2019 at 11:05:25PM +0530, Jagan Teki wrote: > Like other dsi setup timings, or hblk for that matter vblk would > also require compute the timings based payload equation along with > packet overhead. > > But, on the other hand vblk computation is also depends on device > lane number. > - for 4 lane devices, it is computed based on vtotal, packet overhead > along with hblk value. > - for others devices, it is simply 0 > > BSP code from BPI-M64-bsp is computing vblk as for 4-lane devices > (from linux-sunxi > drivers/video/sunxi/disp2/disp/de/lowlevel_sun50iw1/de_dsi.c) > > tmp = (ht*dsi_pixel_bits[format]/8)*vt-(4+dsi_hblk+2); > dsi_vblk = (lane-tmp%lane); > > So, update the vblk timing calculation to support all type of > devices. > > Tested on 2-lane, 4-lane MIPI-DSI LCD panels.
You should be explaining which issue you faced, in which setup, what were its symptoms and how that solution is fixing it. > Signed-off-by: Jagan Teki <ja...@amarulasolutions.com> > Tested-by: Merlijn Wajer <merl...@wizzup.org> > --- > drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 27 +++++++++++++++++++------- > 1 file changed, 20 insertions(+), 7 deletions(-) > > diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > index 140e55f5ed2e..b38358465d87 100644 > --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > @@ -527,6 +527,24 @@ static void sun6i_dsi_setup_format(struct sun6i_dsi *dsi, > SUN6I_DSI_PIXEL_CTL0_FORMAT(fmt)); > } > > +static u16 sun6i_dsi_get_timings_vblk(struct sun6i_dsi *dsi, > + struct drm_display_mode *mode, u16 hblk) > +{ > + struct mipi_dsi_device *device = dsi->device; > + unsigned int Bpp = mipi_dsi_pixel_format_to_bpp(device->format) / 8; > + int tmp; > + > + /* > + * The vertical blank is set using a blanking packet (4 bytes + > + * payload + 2 bytes). Its minimal size is therefore 6 bytes > + */ > +#define VBLK_PACKET_OVERHEAD 6 > + tmp = (mode->htotal * Bpp) * mode->vtotal - > + (hblk + VBLK_PACKET_OVERHEAD); > + > + return (device->lanes - tmp % device->lanes); This should have a comment explaining why it's needed > +} > + > static void sun6i_dsi_setup_timings(struct sun6i_dsi *dsi, > struct drm_display_mode *mode) > { > @@ -586,13 +604,8 @@ static void sun6i_dsi_setup_timings(struct sun6i_dsi > *dsi, > (mode->htotal - (mode->hsync_end - > mode->hsync_start)) * Bpp - > HBLK_PACKET_OVERHEAD); > > - /* > - * And I'm not entirely sure what vblk is about. The driver in > - * Allwinner BSP is using a rather convoluted calculation > - * there only for 4 lanes. However, using 0 (the !4 lanes > - * case) even with a 4 lanes screen seems to work... > - */ > - vblk = 0; > + if (device->lanes == 4) And that can be done in the function itself. Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
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