diff options
Diffstat (limited to 'backend/drm/util.c')
| -rw-r--r-- | backend/drm/util.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/backend/drm/util.c b/backend/drm/util.c index d4ece1f9..560127fa 100644 --- a/backend/drm/util.c +++ b/backend/drm/util.c @@ -3,6 +3,7 @@ #include <drm_fourcc.h> #include <drm_mode.h> #include <drm.h> +#include <libdisplay-info/cvt.h> #include <libdisplay-info/edid.h> #include <libdisplay-info/info.h> #include <stdio.h> @@ -241,3 +242,37 @@ size_t match_obj(size_t num_objs, const uint32_t objs[static restrict num_objs], match_obj_(&st, 0, 0, 0, 0); return st.score; } + +void generate_cvt_mode(drmModeModeInfo *mode, int hdisplay, int vdisplay, + float vrefresh) { + // TODO: depending on capabilities advertised in the EDID, use reduced + // blanking if possible (and update sync polarity) + struct di_cvt_options options = { + .red_blank_ver = DI_CVT_REDUCED_BLANKING_NONE, + .h_pixels = hdisplay, + .v_lines = vdisplay, + .ip_freq_rqd = vrefresh ? vrefresh : 60, + }; + struct di_cvt_timing timing; + di_cvt_compute(&timing, &options); + + uint16_t hsync_start = hdisplay + timing.h_front_porch; + uint16_t vsync_start = timing.v_lines_rnd + timing.v_front_porch; + uint16_t hsync_end = hsync_start + timing.h_sync; + uint16_t vsync_end = vsync_start + timing.v_sync; + + *mode = (drmModeModeInfo){ + .clock = roundf(timing.act_pixel_freq * 1000), + .hdisplay = hdisplay, + .vdisplay = timing.v_lines_rnd, + .hsync_start = hsync_start, + .vsync_start = vsync_start, + .hsync_end = hsync_end, + .vsync_end = vsync_end, + .htotal = hsync_end + timing.h_back_porch, + .vtotal = vsync_end + timing.v_back_porch, + .vrefresh = roundf(timing.act_frame_rate), + .flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_PVSYNC, + }; + snprintf(mode->name, sizeof(mode->name), "%dx%d", hdisplay, vdisplay); +} |