| Message ID | e858ff6509e0d3f657fd9229b28f4ac177a04a76.1549896081.git-series.maxime.ripard@bootlin.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/sun4i: dsi: Add burst mode support | expand |
Hi, On Mon, 2019-02-11 at 15:41 +0100, Maxime Ripard wrote: > The DRQ calculation code in the Allwinner BSP uses the vertical front > porch value as the condition, but we're using the video back porch. > > Since I always confuse the two, and I'm the original author of that code, I > guess I deserved a brown paper bag. > > Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com> Assuming that the BSP's hbp is referring to the back porch only, then calculating ht - x - hbp does give us the front porch + hsync length. Well, let's guess that this about the front porch only until we know better. It's certainly better than using the back porch anyway :) Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com> Cheers, Paul > --- > 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 2518a0d7567c..8e6392831e9d 100644 > --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > @@ -372,9 +372,9 @@ static void sun6i_dsi_setup_burst(struct sun6i_dsi *dsi, > struct mipi_dsi_device *device = dsi->device; > u32 val = 0; > > - if ((mode->hsync_end - mode->hdisplay) > 20) { > + if ((mode->hsync_start - mode->hdisplay) > 20) { > /* Maaaaaagic */ > - u16 drq = (mode->hsync_end - mode->hdisplay) - 20; > + u16 drq = (mode->hsync_start - mode->hdisplay) - 20; > > drq *= mipi_dsi_pixel_format_to_bpp(device->format); > drq /= 32;
On Wed, Feb 13, 2019 at 03:33:38PM +0100, Paul Kocialkowski wrote: > Hi, > > On Mon, 2019-02-11 at 15:41 +0100, Maxime Ripard wrote: > > The DRQ calculation code in the Allwinner BSP uses the vertical front > > porch value as the condition, but we're using the video back porch. > > > > Since I always confuse the two, and I'm the original author of that code, I > > guess I deserved a brown paper bag. > > > > Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com> > > Assuming that the BSP's hbp is referring to the back porch only, then > calculating ht - x - hbp does give us the front porch + hsync length. > > Well, let's guess that this about the front porch only until we know > better. It's certainly better than using the back porch anyway :) After discussing it with Paul, we decided to drop that patch since it would make the backporch definition inconsistent in the driver. Maxime
diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c index 2518a0d7567c..8e6392831e9d 100644 --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c @@ -372,9 +372,9 @@ static void sun6i_dsi_setup_burst(struct sun6i_dsi *dsi, struct mipi_dsi_device *device = dsi->device; u32 val = 0; - if ((mode->hsync_end - mode->hdisplay) > 20) { + if ((mode->hsync_start - mode->hdisplay) > 20) { /* Maaaaaagic */ - u16 drq = (mode->hsync_end - mode->hdisplay) - 20; + u16 drq = (mode->hsync_start - mode->hdisplay) - 20; drq *= mipi_dsi_pixel_format_to_bpp(device->format); drq /= 32;
The DRQ calculation code in the Allwinner BSP uses the vertical front porch value as the condition, but we're using the video back porch. Since I always confuse the two, and I'm the original author of that code, I guess I deserved a brown paper bag. Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com> --- drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)