Hi, Am Montag, 17. Juli 2023, 08:18:27 CEST schrieb Liu Ying: > To get better accuration, use pixel clock rate to calculate lbcc instead of > lane_mbps since the pixel clock rate is in KHz while lane_mbps is in MHz. > Without this, distorted image can be seen on a HDMI monitor connected with > i.MX93 11x11 EVK through ADV7535 DSI to HDMI bridge in 1920x1080p@60 video > mode. > > Signed-off-by: Liu Ying <victor....@nxp.com>
looks like I'm late to the party, but this change breaks the display output my px30 minievb with the xinpeng xpp055c272 dsi display [0]. Found this commit via git bisection and added a bit of debug output to compare the value differences for the old and new calculation: [ 34.810722] dw_mipi_dsi_get_hcomponent_lbcc: old lbcc: 810 * 480 * 1000 / 8 [ 34.810749] dw_mipi_dsi_get_hcomponent_lbcc: new lbcc: 810 * 64000 * 24 / (4 * 8) [ 34.810756] dw_mipi_dsi_get_hcomponent_lbcc: old lbcc: 48600000, new lbcc: 38880000 [ 34.810762] dw_mipi_dsi_get_hcomponent_lbcc: old lbcc: 10 * 480 * 1000 / 8 [ 34.810767] dw_mipi_dsi_get_hcomponent_lbcc: new lbcc: 10 * 64000 * 24 / (4 * 8) [ 34.810773] dw_mipi_dsi_get_hcomponent_lbcc: old lbcc: 600000, new lbcc: 480000 [ 34.810778] dw_mipi_dsi_get_hcomponent_lbcc: old lbcc: 40 * 480 * 1000 / 8 [ 34.810783] dw_mipi_dsi_get_hcomponent_lbcc: new lbcc: 40 * 64000 * 24 / (4 * 8) [ 34.810789] dw_mipi_dsi_get_hcomponent_lbcc: old lbcc: 2400000, new lbcc: 1920000 With the new lbcc I get a blank dsi panel and just going back to the old calculation of lbcc restores the image. I don't have that much in-depth knowledge about dsi stuff and the original panel times also "just" came from the vendor tree, but I really would like to keep that display working ;-) . Do you have any idea which way to go to fix this? Thanks Heiko [0] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/rockchip/px30-evb.dts#n138 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/panel/panel-xinpeng-xpp055c272.c > --- > drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c > b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c > index c754d55f71d1..332388fd86da 100644 > --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c > +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c > @@ -12,6 +12,7 @@ > #include <linux/component.h> > #include <linux/debugfs.h> > #include <linux/iopoll.h> > +#include <linux/math64.h> > #include <linux/media-bus-format.h> > #include <linux/module.h> > #include <linux/of_device.h> > @@ -762,8 +763,15 @@ static u32 dw_mipi_dsi_get_hcomponent_lbcc(struct > dw_mipi_dsi *dsi, > u32 hcomponent) > { > u32 frac, lbcc; > + int bpp; > > - lbcc = hcomponent * dsi->lane_mbps * MSEC_PER_SEC / 8; > + bpp = mipi_dsi_pixel_format_to_bpp(dsi->format); > + if (bpp < 0) { > + dev_err(dsi->dev, "failed to get bpp\n"); > + return 0; > + } > + > + lbcc = div_u64((u64)hcomponent * mode->clock * bpp, dsi->lanes * 8);
