drm_gtf_mode_complex(struct drm_device *dev, int hdisplay, int vdisplay, int vrefresh, bool interlaced, int margins, int GTF_M, int GTF_2C, int GTF_K, int GTF_2J) { /* 1) top/bottom margin size (% of height) - default: 1.8, */ #define GTF_MARGIN_PERCENTAGE 18 /* 2) character cell horizontal granularity (pixels) - default 8 */ #define GTF_CELL_GRAN 8 /* 3) Minimum vertical porch (lines) - default 3 */ #define GTF_MIN_V_PORCH 1 /* width of vsync in lines */ #define V_SYNC_RQD 3 /* width of hsync as % of total line */ #define H_SYNC_PERCENT 8 /* min time of vsync + back porch (microsec) */ #define MIN_VSYNC_PLUS_BP 550 /* C' and M' are part of the Blanking Duty Cycle computation */ #define GTF_C_PRIME ((((GTF_2C - GTF_2J) * GTF_K / 256) + GTF_2J) / 2) #define GTF_M_PRIME (GTF_K * GTF_M / 256) struct drm_display_mode *drm_mode; unsigned int hdisplay_rnd, vdisplay_rnd, vfieldrate_rqd; int top_margin, bottom_margin; int interlace; unsigned int hfreq_est; int vsync_plus_bp, vback_porch; unsigned int vtotal_lines, vfieldrate_est, hperiod; unsigned int vfield_rate, vframe_rate; int left_margin, right_margin; unsigned int total_active_pixels, ideal_duty_cycle; unsigned int hblank, total_pixels, pixel_freq; int hsync, hfront_porch, vodd_front_porch_lines; unsigned int tmp1, tmp2; drm_mode = drm_mode_create(dev); if (!drm_mode) return NULL; /* 1. In order to give correct results, the number of horizontal * pixels requested is first processed to ensure that it is divisible * by the character size, by rounding it to the nearest character * cell boundary: */ hdisplay_rnd = (hdisplay + GTF_CELL_GRAN / 2) / GTF_CELL_GRAN; hdisplay_rnd = hdisplay_rnd * GTF_CELL_GRAN; /* 2. If interlace is requested, the number of vertical lines assumed * by the calculation must be halved, as the computation calculates * the number of vertical lines per field. */ if (interlaced) vdisplay_rnd = vdisplay / 2; else vdisplay_rnd = vdisplay; /* 3. Find the frame rate required: */ if (interlaced) vfieldrate_rqd = vrefresh * 2; else vfieldrate_rqd = vrefresh; /* 4. Find number of lines in Top margin: */ top_margin = 0; if (margins) top_margin = (vdisplay_rnd * GTF_MARGIN_PERCENTAGE + 500) / 1000; /* 5. Find number of lines in bottom margin: */ bottom_margin = top_margin; /* 6. If interlace is required, then set variable interlace: */ if (interlaced) interlace = 1; else interlace = 0; /* 7. Estimate the Horizontal frequency */ { tmp1 = (1000000 - MIN_VSYNC_PLUS_BP * vfieldrate_rqd) / 500; tmp2 = (vdisplay_rnd + 2 * top_margin + GTF_MIN_V_PORCH) * 2 + interlace; hfreq_est = (tmp2 * 1000 * vfieldrate_rqd) / tmp1; } /* 8. Find the number of lines in V sync + back porch */ /* [V SYNC+BP] = RINT(([MIN VSYNC+BP] * hfreq_est / 1000000)) */ vsync_plus_bp = MIN_VSYNC_PLUS_BP * hfreq_est / 1000; vsync_plus_bp = (vsync_plus_bp + 500) / 1000; /* 9. Find the number of lines in V back porch alone: */ vback_porch = vsync_plus_bp - V_SYNC_RQD; /* 10. Find the total number of lines in Vertical field period: */ vtotal_lines = vdisplay_rnd + top_margin + bottom_margin + vsync_plus_bp + GTF_MIN_V_PORCH; /* 11. Estimate the Vertical field frequency: */ vfieldrate_est = hfreq_est / vtotal_lines; /* 12. Find the actual horizontal period: */ hperiod = 1000000 / (vfieldrate_rqd * vtotal_lines); /* 13. Find the actual Vertical field frequency: */ vfield_rate = hfreq_est / vtotal_lines; /* 14. Find the Vertical frame frequency: */ if (interlaced) vframe_rate = vfield_rate / 2; else vframe_rate = vfield_rate; /* 15. Find number of pixels in left margin: */ if (margins) left_margin = (hdisplay_rnd * GTF_MARGIN_PERCENTAGE + 500) / 1000; else left_margin = 0; /* 16.Find number of pixels in right margin: */ right_margin = left_margin; /* 17.Find total number of active pixels in image and left and right */ total_active_pixels = hdisplay_rnd + left_margin + right_margin; /* 18.Find the ideal blanking duty cycle from blanking duty cycle */ ideal_duty_cycle = GTF_C_PRIME * 1000 - (GTF_M_PRIME * 1000000 / hfreq_est); /* FIX (DF-3682): reject bogus EDID GTF2 parameters that would make * the blanking duty cycle denominator zero or the blanking negative */ if (ideal_duty_cycle <= 0 || ideal_duty_cycle >= 100000) { free(drm_mode); return NULL; } /* 19.Find the number of pixels in the blanking time to the nearest * double character cell: */ hblank = total_active_pixels * ideal_duty_cycle / (100000 - ideal_duty_cycle); hblank = (hblank + GTF_CELL_GRAN) / (2 * GTF_CELL_GRAN); hblank = hblank * 2 * GTF_CELL_GRAN; /* 20.Find total number of pixels: */ total_pixels = total_active_pixels + hblank; /* 21.Find pixel clock frequency: */ pixel_freq = total_pixels * hfreq_est / 1000; /* Stage 1 computations are now complete; I should really pass * the results to another function and do the Stage 2 computations, * but I only need a few more values so I'll just append the * computations here for now */ /* 17. Find the number of pixels in the horizontal sync period: */ hsync = H_SYNC_PERCENT * total_pixels / 100; hsync = (hsync + GTF_CELL_GRAN / 2) / GTF_CELL_GRAN; hsync = hsync * GTF_CELL_GRAN; /* 18. Find the number of pixels in horizontal front porch period */ hfront_porch = hblank / 2 - hsync; /* 36. Find the number of lines in the odd front porch period: */ vodd_front_porch_lines = GTF_MIN_V_PORCH ; /* finally, pack the results in the mode struct */ drm_mode->hdisplay = hdisplay_rnd; drm_mode->hsync_start = hdisplay_rnd + hfront_porch; drm_mode->hsync_end = drm_mode->hsync_start + hsync; drm_mode->htotal = total_pixels; drm_mode->vdisplay = vdisplay_rnd; drm_mode->vsync_start = vdisplay_rnd + vodd_front_porch_lines; drm_mode->vsync_end = drm_mode->vsync_start + V_SYNC_RQD; drm_mode->vtotal = vtotal_lines; drm_mode->clock = pixel_freq; if (interlaced) { drm_mode->vtotal *= 2; drm_mode->flags |= DRM_MODE_FLAG_INTERLACE; } drm_mode_set_name(drm_mode); if (GTF_M == 600 && GTF_2C == 80 && GTF_K == 128 && GTF_2J == 40) drm_mode->flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_PVSYNC; else drm_mode->flags = DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_NVSYNC; return drm_mode; }