fbmon.c

Linux环境下视频显示卡设备的驱动程序源代码

	parse_vendor_block(edid + ID_MANUFACTURER_NAME, specs);

	block = edid + DETAILED_TIMING_DESCRIPTIONS_START;
	for (i = 0; i < 4; i++, block += DETAILED_TIMING_DESCRIPTION_SIZE) {
		if (edid_is_serial_block(block)) {
			copy_string(block, specs->serial_no);
			DPRINTK("   Serial Number: %s\n", specs->serial_no);
		} else if (edid_is_ascii_block(block)) {
			copy_string(block, specs->ascii);
			DPRINTK("   ASCII Block: %s\n", specs->ascii);
		} else if (edid_is_monitor_block(block)) {
			copy_string(block, specs->monitor);
			DPRINTK("   Monitor Name: %s\n", specs->monitor);
		}
	}

	DPRINTK("   Display Characteristics:\n");
	get_monspecs(edid, specs);

	specs->modedb = fb_create_modedb(edid, &specs->modedb_len);

	/*
	 * Workaround for buggy EDIDs that sets that the first
	 * detailed timing is preferred but has not detailed
	 * timing specified
	 */
	for (i = 0; i < specs->modedb_len; i++) {
		if (specs->modedb[i].flag & FB_MODE_IS_DETAILED) {
			found = 1;
			break;
		}
	}

	if (!found)
		specs->misc &= ~FB_MISC_1ST_DETAIL;

	DPRINTK("========================================\n");
}

/*
 * VESA Generalized Timing Formula (GTF)
 */

#define FLYBACK                     550
#define V_FRONTPORCH                1
#define H_OFFSET                    40
#define H_SCALEFACTOR               20
#define H_BLANKSCALE                128
#define H_GRADIENT                  600
#define C_VAL                       30
#define M_VAL                       300

struct __fb_timings {
	u32 dclk;
	u32 hfreq;
	u32 vfreq;
	u32 hactive;
	u32 vactive;
	u32 hblank;
	u32 vblank;
	u32 htotal;
	u32 vtotal;
};

/**
 * fb_get_vblank - get vertical blank time
 * @hfreq: horizontal freq
 *
 * DESCRIPTION:
 * vblank = right_margin + vsync_len + left_margin
 *
 *    given: right_margin = 1 (V_FRONTPORCH)
 *           vsync_len    = 3
 *           flyback      = 550
 *
 *                          flyback * hfreq
 *           left_margin  = --------------- - vsync_len
 *                           1000000
 */
static u32 fb_get_vblank(u32 hfreq)
{
	u32 vblank;

	vblank = (hfreq * FLYBACK)/1000;
	vblank = (vblank + 500)/1000;
	return (vblank + V_FRONTPORCH);
}

/**
 * fb_get_hblank_by_freq - get horizontal blank time given hfreq
 * @hfreq: horizontal freq
 * @xres: horizontal resolution in pixels
 *
 * DESCRIPTION:
 *
 *           xres * duty_cycle
 * hblank = ------------------
 *           100 - duty_cycle
 *
 * duty cycle = percent of htotal assigned to inactive display
 * duty cycle = C - (M/Hfreq)
 *
 * where: C = ((offset - scale factor) * blank_scale)
 *            -------------------------------------- + scale factor
 *                        256
 *        M = blank_scale * gradient
 *
 */
static u32 fb_get_hblank_by_hfreq(u32 hfreq, u32 xres)
{
	u32 c_val, m_val, duty_cycle, hblank;

	c_val = (((H_OFFSET - H_SCALEFACTOR) * H_BLANKSCALE)/256 +
		 H_SCALEFACTOR) * 1000;
	m_val = (H_BLANKSCALE * H_GRADIENT)/256;
	m_val = (m_val * 1000000)/hfreq;
	duty_cycle = c_val - m_val;
	hblank = (xres * duty_cycle)/(100000 - duty_cycle);
	return (hblank);
}

/**
 * fb_get_hblank_by_dclk - get horizontal blank time given pixelclock
 * @dclk: pixelclock in Hz
 * @xres: horizontal resolution in pixels
 *
 * DESCRIPTION:
 *
 *           xres * duty_cycle
 * hblank = ------------------
 *           100 - duty_cycle
 *
 * duty cycle = percent of htotal assigned to inactive display
 * duty cycle = C - (M * h_period)
 *
 * where: h_period = SQRT(100 - C + (0.4 * xres * M)/dclk) + C - 100
 *                   -----------------------------------------------
 *                                    2 * M
 *        M = 300;
 *        C = 30;

 */
static u32 fb_get_hblank_by_dclk(u32 dclk, u32 xres)
{
	u32 duty_cycle, h_period, hblank;

	dclk /= 1000;
	h_period = 100 - C_VAL;
	h_period *= h_period;
	h_period += (M_VAL * xres * 2 * 1000)/(5 * dclk);
	h_period *= 10000;

	h_period = int_sqrt(h_period);
	h_period -= (100 - C_VAL) * 100;
	h_period *= 1000;
	h_period /= 2 * M_VAL;

	duty_cycle = C_VAL * 1000 - (M_VAL * h_period)/100;
	hblank = (xres * duty_cycle)/(100000 - duty_cycle) + 8;
	hblank &= ~15;
	return (hblank);
}

/**
 * fb_get_hfreq - estimate hsync
 * @vfreq: vertical refresh rate
 * @yres: vertical resolution
 *
 * DESCRIPTION:
 *
 *          (yres + front_port) * vfreq * 1000000
 * hfreq = -------------------------------------
 *          (1000000 - (vfreq * FLYBACK)
 *
 */

static u32 fb_get_hfreq(u32 vfreq, u32 yres)
{
	u32 divisor, hfreq;

	divisor = (1000000 - (vfreq * FLYBACK))/1000;
	hfreq = (yres + V_FRONTPORCH) * vfreq  * 1000;
	return (hfreq/divisor);
}

static void fb_timings_vfreq(struct __fb_timings *timings)
{
	timings->hfreq = fb_get_hfreq(timings->vfreq, timings->vactive);
	timings->vblank = fb_get_vblank(timings->hfreq);
	timings->vtotal = timings->vactive + timings->vblank;
	timings->hblank = fb_get_hblank_by_hfreq(timings->hfreq,
						 timings->hactive);
	timings->htotal = timings->hactive + timings->hblank;
	timings->dclk = timings->htotal * timings->hfreq;
}

static void fb_timings_hfreq(struct __fb_timings *timings)
{
	timings->vblank = fb_get_vblank(timings->hfreq);
	timings->vtotal = timings->vactive + timings->vblank;
	timings->vfreq = timings->hfreq/timings->vtotal;
	timings->hblank = fb_get_hblank_by_hfreq(timings->hfreq,
						 timings->hactive);
	timings->htotal = timings->hactive + timings->hblank;
	timings->dclk = timings->htotal * timings->hfreq;
}

static void fb_timings_dclk(struct __fb_timings *timings)
{
	timings->hblank = fb_get_hblank_by_dclk(timings->dclk,
						timings->hactive);
	timings->htotal = timings->hactive + timings->hblank;
	timings->hfreq = timings->dclk/timings->htotal;
	timings->vblank = fb_get_vblank(timings->hfreq);
	timings->vtotal = timings->vactive + timings->vblank;
	timings->vfreq = timings->hfreq/timings->vtotal;
}

/*
 * fb_get_mode - calculates video mode using VESA GTF
 * @flags: if: 0 - maximize vertical refresh rate
 *             1 - vrefresh-driven calculation;
 *             2 - hscan-driven calculation;
 *             3 - pixelclock-driven calculation;
 * @val: depending on @flags, ignored, vrefresh, hsync or pixelclock
 * @var: pointer to fb_var_screeninfo
 * @info: pointer to fb_info
 *
 * DESCRIPTION:
 * Calculates video mode based on monitor specs using VESA GTF.
 * The GTF is best for VESA GTF compliant monitors but is
 * specifically formulated to work for older monitors as well.
 *
 * If @flag==0, the function will attempt to maximize the
 * refresh rate.  Otherwise, it will calculate timings based on
 * the flag and accompanying value.
 *
 * If FB_IGNOREMON bit is set in @flags, monitor specs will be
 * ignored and @var will be filled with the calculated timings.
 *
 * All calculations are based on the VESA GTF Spreadsheet
 * available at VESA's public ftp (http://www.vesa.org).
 *
 * NOTES:
 * The timings generated by the GTF will be different from VESA
 * DMT.  It might be a good idea to keep a table of standard
 * VESA modes as well.  The GTF may also not work for some displays,
 * such as, and especially, analog TV.
 *
 * REQUIRES:
 * A valid info->monspecs, otherwise 'safe numbers' will be used.
 */
int fb_get_mode(int flags, u32 val, struct fb_var_screeninfo *var, struct fb_info *info)
{
	struct __fb_timings *timings;
	u32 interlace = 1, dscan = 1;
	u32 hfmin, hfmax, vfmin, vfmax, dclkmin, dclkmax, err = 0;


	timings = kzalloc(sizeof(struct __fb_timings), GFP_KERNEL);

	if (!timings)
		return -ENOMEM;

	/*
	 * If monspecs are invalid, use values that are enough
	 * for 640x480@60
	 */
	if (!info || !info->monspecs.hfmax || !info->monspecs.vfmax ||
	    !info->monspecs.dclkmax ||
	    info->monspecs.hfmax < info->monspecs.hfmin ||
	    info->monspecs.vfmax < info->monspecs.vfmin ||
	    info->monspecs.dclkmax < info->monspecs.dclkmin) {
		hfmin = 29000; hfmax = 30000;
		vfmin = 60; vfmax = 60;
		dclkmin = 0; dclkmax = 25000000;
	} else {
		hfmin = info->monspecs.hfmin;
		hfmax = info->monspecs.hfmax;
		vfmin = info->monspecs.vfmin;
		vfmax = info->monspecs.vfmax;
		dclkmin = info->monspecs.dclkmin;
		dclkmax = info->monspecs.dclkmax;
	}

	timings->hactive = var->xres;
	timings->vactive = var->yres;
	if (var->vmode & FB_VMODE_INTERLACED) {
		timings->vactive /= 2;
		interlace = 2;
	}
	if (var->vmode & FB_VMODE_DOUBLE) {
		timings->vactive *= 2;
		dscan = 2;
	}

	switch (flags & ~FB_IGNOREMON) {
	case FB_MAXTIMINGS: /* maximize refresh rate */
		timings->hfreq = hfmax;
		fb_timings_hfreq(timings);
		if (timings->vfreq > vfmax) {
			timings->vfreq = vfmax;
			fb_timings_vfreq(timings);
		}
		if (timings->dclk > dclkmax) {
			timings->dclk = dclkmax;
			fb_timings_dclk(timings);
		}
		break;
	case FB_VSYNCTIMINGS: /* vrefresh driven */
		timings->vfreq = val;
		fb_timings_vfreq(timings);
		break;
	case FB_HSYNCTIMINGS: /* hsync driven */
		timings->hfreq = val;
		fb_timings_hfreq(timings);
		break;
	case FB_DCLKTIMINGS: /* pixelclock driven */
		timings->dclk = PICOS2KHZ(val) * 1000;
		fb_timings_dclk(timings);
		break;
	default:
		err = -EINVAL;

	}

	if (err || (!(flags & FB_IGNOREMON) &&
	    (timings->vfreq < vfmin || timings->vfreq > vfmax ||
	     timings->hfreq < hfmin || timings->hfreq > hfmax ||
	     timings->dclk < dclkmin || timings->dclk > dclkmax))) {
		err = -EINVAL;
	} else {
		var->pixclock = KHZ2PICOS(timings->dclk/1000);
		var->hsync_len = (timings->htotal * 8)/100;
		var->right_margin = (timings->hblank/2) - var->hsync_len;
		var->left_margin = timings->hblank - var->right_margin -
			var->hsync_len;
		var->vsync_len = (3 * interlace)/dscan;
		var->lower_margin = (1 * interlace)/dscan;
		var->upper_margin = (timings->vblank * interlace)/dscan -
			(var->vsync_len + var->lower_margin);
	}

	kfree(timings);
	return err;
}
#else
int fb_parse_edid(unsigned char *edid, struct fb_var_screeninfo *var)
{
	return 1;
}
void fb_edid_to_monspecs(unsigned char *edid, struct fb_monspecs *specs)
{
	specs = NULL;
}
void fb_destroy_modedb(struct fb_videomode *modedb)
{
}
int fb_get_mode(int flags, u32 val, struct fb_var_screeninfo *var,
		struct fb_info *info)
{
	return -EINVAL;
}
#endif /* CONFIG_FB_MODE_HELPERS */

/*
 * fb_validate_mode - validates var against monitor capabilities
 * @var: pointer to fb_var_screeninfo
 * @info: pointer to fb_info
 *
 * DESCRIPTION:
 * Validates video mode against monitor capabilities specified in
 * info->monspecs.
 *
 * REQUIRES:
 * A valid info->monspecs.
 */
int fb_validate_mode(const struct fb_var_screeninfo *var, struct fb_info *info)
{
	u32 hfreq, vfreq, htotal, vtotal, pixclock;
	u32 hfmin, hfmax, vfmin, vfmax, dclkmin, dclkmax;

	/*
	 * If monspecs are invalid, use values that are enough
	 * for 640x480@60
	 */
	if (!info->monspecs.hfmax || !info->monspecs.vfmax ||
	    !info->monspecs.dclkmax ||
	    info->monspecs.hfmax < info->monspecs.hfmin ||
	    info->monspecs.vfmax < info->monspecs.vfmin ||
	    info->monspecs.dclkmax < info->monspecs.dclkmin) {
		hfmin = 29000; hfmax = 30000;
		vfmin = 60; vfmax = 60;
		dclkmin = 0; dclkmax = 25000000;
	} else {
		hfmin = info->monspecs.hfmin;
		hfmax = info->monspecs.hfmax;
		vfmin = info->monspecs.vfmin;
		vfmax = info->monspecs.vfmax;
		dclkmin = info->monspecs.dclkmin;
		dclkmax = info->monspecs.dclkmax;
	}

	if (!var->pixclock)
		return -EINVAL;
	pixclock = PICOS2KHZ(var->pixclock) * 1000;

	htotal = var->xres + var->right_margin + var->hsync_len +
		var->left_margin;
	vtotal = var->yres + var->lower_margin + var->vsync_len +
		var->upper_margin;

	if (var->vmode & FB_VMODE_INTERLACED)
		vtotal /= 2;
	if (var->vmode & FB_VMODE_DOUBLE)
		vtotal *= 2;

	hfreq = pixclock/htotal;
	hfreq = (hfreq + 500) / 1000 * 1000;

	vfreq = hfreq/vtotal;

	return (vfreq < vfmin || vfreq > vfmax ||
		hfreq < hfmin || hfreq > hfmax ||
		pixclock < dclkmin || pixclock > dclkmax) ?
		-EINVAL : 0;
}

#if defined(CONFIG_FIRMWARE_EDID) && defined(CONFIG_X86)

/*
 * We need to ensure that the EDID block is only returned for
 * the primary graphics adapter.
 */

const unsigned char *fb_firmware_edid(struct device *device)
{
	struct pci_dev *dev = NULL;
	struct resource *res = NULL;
	unsigned char *edid = NULL;

	if (device)
		dev = to_pci_dev(device);

	if (dev)
		res = &dev->resource[PCI_ROM_RESOURCE];

	if (res && res->flags & IORESOURCE_ROM_SHADOW)
		edid = edid_info.dummy;

	return edid;
}
#else
const unsigned char *fb_firmware_edid(struct device *device)
{
	return NULL;
}
#endif
EXPORT_SYMBOL(fb_firmware_edid);

EXPORT_SYMBOL(fb_parse_edid);
EXPORT_SYMBOL(fb_edid_to_monspecs);
EXPORT_SYMBOL(fb_get_mode);
EXPORT_SYMBOL(fb_validate_mode);
EXPORT_SYMBOL(fb_destroy_modedb);