On Mon, Mar 4, 2019 at 9:24 PM Maxime Ripard <[email protected]> wrote: > > On Sun, Mar 03, 2019 at 11:05:23PM +0530, Jagan Teki wrote: > > Loop N1 instruction delay for burst mode devices are computed > > based on horizontal sync and porch timing values. > > > > The current driver is using u16 type for computing this hsync_porch > > value, which would failed to fit within the u16 type for large sync > > and porch timings devices. This would result in hsync_porch overflow > > and eventually computed wrong instruction delay value. > > > > Example, timings, where it produces the overflow > > { > > .hdisplay = 1080, > > .hsync_start = 1080 + 408, > > .hsync_end = 1080 + 408 + 4, > > .htotal = 1080 + 408 + 4 + 38, > > } > > > > It reproduces the desired delay value 65487 but the correct working > > value should be 7. > > > > So, Fix it by computing hsync_porch value separately with u32 type. > > > > Fixes: 1c1a7aa3663c ("drm/sun4i: dsi: Add burst support") > > Signed-off-by: Jagan Teki <[email protected]> > > Tested-by: Merlijn Wajer <[email protected]> > > --- > > drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > index 6ff585055a07..465e7fc57899 100644 > > --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > @@ -457,8 +457,9 @@ static void sun6i_dsi_setup_inst_loop(struct sun6i_dsi > > *dsi, > > u16 delay = 50 - 1; > > > > if (device->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) { > > - delay = (mode->htotal - mode->hdisplay) * 150; > > - delay /= (mode->clock / 1000) * 8; > > + u32 hsync_porch = (mode->htotal - mode->hdisplay); > > + > > + delay = ((hsync_porch * 150) / ((mode->clock / 1000) * 8)); > > shouldn't we keep the multiplication by 150 in the u32 assignation?
Yes, ie true. will move it. _______________________________________________ dri-devel mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/dri-devel
