diff options
| -rw-r--r-- | drivers/gpu/drm/drm_modes.c | 197 | ||||
| -rw-r--r-- | include/drm/drm_crtc.h | 3 |
2 files changed, 200 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c index 0dbc7e4f8643..fd489d76fbbc 100644 --- a/drivers/gpu/drm/drm_modes.c +++ b/drivers/gpu/drm/drm_modes.c @@ -9,6 +9,7 @@ * Copyright © 2007-2008 Intel Corporation * Jesse Barnes <jesse.barnes@intel.com> * Copyright 2005-2006 Luc Verhaegen + * Copyright (c) 2001, Andy Ritger aritger@nvidia.com * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), @@ -281,6 +282,202 @@ struct drm_display_mode *drm_cvt_mode(struct drm_device *dev, int hdisplay, EXPORT_SYMBOL(drm_cvt_mode); /** + * drm_gtf_mode - create the modeline based on GTF algorithm + * + * @dev :drm device + * @hdisplay :hdisplay size + * @vdisplay :vdisplay size + * @vrefresh :vrefresh rate. + * @interlaced :whether the interlace is supported + * @margins :whether the margin is supported + * + * LOCKING. + * none. + * + * return the modeline based on GTF algorithm + * + * This function is to create the modeline based on the GTF algorithm. + * Generalized Timing Formula is derived from: + * GTF Spreadsheet by Andy Morrish (1/5/97) + * available at http://www.vesa.org + * + * And it is copied from the file of xserver/hw/xfree86/modes/xf86gtf.c. + * What I have done is to translate it by using integer calculation. + * I also refer to the function of fb_get_mode in the file of + * drivers/video/fbmon.c + */ +struct drm_display_mode *drm_gtf_mode(struct drm_device *dev, int hdisplay, + int vdisplay, int vrefresh, + bool interlaced, int margins) +{ + /* 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 + /* blanking formula gradient */ +#define GTF_M 600 + /* blanking formula offset */ +#define GTF_C 40 + /* blanking formula scaling factor */ +#define GTF_K 128 + /* blanking formula scaling factor */ +#define GTF_J 20 + /* C' and M' are part of the Blanking Duty Cycle computation */ +#define GTF_C_PRIME (((GTF_C - GTF_J) * GTF_K / 256) + GTF_J) +#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); + /* 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; + + drm_mode_set_name(drm_mode); + drm_mode->flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_PVSYNC; + + if (interlaced) { + drm_mode->vtotal *= 2; + drm_mode->flags |= DRM_MODE_FLAG_INTERLACE; + } + + return drm_mode; +} +EXPORT_SYMBOL(drm_gtf_mode); +/** * drm_mode_set_name - set the name on a mode * @mode: name will be set in this mode * diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h index 820bc0977e5e..125994d8ac0b 100644 --- a/include/drm/drm_crtc.h +++ b/include/drm/drm_crtc.h @@ -739,4 +739,7 @@ extern bool drm_detect_hdmi_monitor(struct edid *edid); extern struct drm_display_mode *drm_cvt_mode(struct drm_device *dev, int hdisplay, int vdisplay, int vrefresh, bool reduced, bool interlaced); +extern struct drm_display_mode *drm_gtf_mode(struct drm_device *dev, + int hdisplay, int vdisplay, int vrefresh, + bool interlaced, int margins); #endif /* __DRM_CRTC_H__ */ |