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Commit 58e7c3b0 authored by Bernie Thompson's avatar Bernie Thompson Committed by Florian Tobias Schandinat
Browse files

udlfb: add more comprehensive support for DPMS FB_BLANK_* modes 



Fixes earlier problems where monitor would not return from blank

Test with any DisplayLink-based USB 2.0 graphics adapter
sudo nano /sys/class/graphics/fb?/blank
and write out single digit FB_BLANK_* code from include/linux/fb.h

Supports on (0), blank (1), suspend (2,3), powerdown (4)

Signed-off-by: default avatarBernie Thompson <bernie@plugable.com>
Signed-off-by: default avatarFlorian Tobias Schandinat <FlorianSchandinat@gmx.de>
parent 3c470f33

drivers/video/udlfb.c

+73 −24
Original line number Diff line number Diff line
@@ -94,17 +94,39 @@ static char *dlfb_vidreg_unlock(char *buf) 
}



/*

 * On/Off for driving the DisplayLink framebuffer to the display

 *  0x00 H and V sync on

 *  0x01 H and V sync off (screen blank but powered)

 *  0x07 DPMS powerdown (requires modeset to come back)

 * Map FB_BLANK_* to DisplayLink register

 * DLReg FB_BLANK_*

 * ----- -----------------------------

 *  0x00 FB_BLANK_UNBLANK (0)

 *  0x01 FB_BLANK (1)

 *  0x03 FB_BLANK_VSYNC_SUSPEND (2)

 *  0x05 FB_BLANK_HSYNC_SUSPEND (3)

 *  0x07 FB_BLANK_POWERDOWN (4) Note: requires modeset to come back

 */

static char *dlfb_enable_hvsync(char *buf, bool enable)

static char *dlfb_blanking(char *buf, int fb_blank)

{

	if (enable)

		return dlfb_set_register(buf, 0x1F, 0x00);

	else

		return dlfb_set_register(buf, 0x1F, 0x07);

	u8 reg;



	switch (fb_blank) {

	case FB_BLANK_POWERDOWN:

		reg = 0x07;

		break;

	case FB_BLANK_HSYNC_SUSPEND:

		reg = 0x05;

		break;

	case FB_BLANK_VSYNC_SUSPEND:

		reg = 0x03;

		break;

	case FB_BLANK_NORMAL:

		reg = 0x01;

		break;

	default:

		reg = 0x00;

	}



	buf = dlfb_set_register(buf, 0x1F, reg);



	return buf;

}



static char *dlfb_set_color_depth(char *buf, u8 selection)
@@ -272,13 +294,15 @@ static int dlfb_set_video_mode(struct dlfb_data *dev, 
	wrptr = dlfb_set_base8bpp(wrptr, dev->info->fix.smem_len);



	wrptr = dlfb_set_vid_cmds(wrptr, var);

	wrptr = dlfb_enable_hvsync(wrptr, true);

	wrptr = dlfb_blanking(wrptr, FB_BLANK_UNBLANK);

	wrptr = dlfb_vidreg_unlock(wrptr);



	writesize = wrptr - buf;



	retval = dlfb_submit_urb(dev, urb, writesize);



	dev->blank_mode = FB_BLANK_UNBLANK;



	return retval;

}
@@ -1039,31 +1063,56 @@ static int dlfb_ops_set_par(struct fb_info *info) 
	return result;

}



/* To fonzi the jukebox (e.g. make blanking changes take effect) */

static char *dlfb_dummy_render(char *buf)

{

	*buf++ = 0xAF;

	*buf++ = 0x6A; /* copy */

	*buf++ = 0x00; /* from address*/

	*buf++ = 0x00;

	*buf++ = 0x00;

	*buf++ = 0x01; /* one pixel */

	*buf++ = 0x00; /* to address */

	*buf++ = 0x00;

	*buf++ = 0x00;

	return buf;

}



/*

 * In order to come back from full DPMS off, we need to set the mode again

 */

static int dlfb_ops_blank(int blank_mode, struct fb_info *info)

{

	struct dlfb_data *dev = info->par;



	if (blank_mode != FB_BLANK_UNBLANK) {

	char *bufptr;

	struct urb *urb;



	pr_info("/dev/fb%d FB_BLANK mode %d --> %d\n",

		info->node, dev->blank_mode, blank_mode);



	if ((dev->blank_mode == FB_BLANK_POWERDOWN) &&

	    (blank_mode != FB_BLANK_POWERDOWN)) {



		/* returning from powerdown requires a fresh modeset */

		dlfb_set_video_mode(dev, &info->var);

	}



	urb = dlfb_get_urb(dev);

	if (!urb)

		return 0;



	bufptr = (char *) urb->transfer_buffer;

	bufptr = dlfb_vidreg_lock(bufptr);

		bufptr = dlfb_enable_hvsync(bufptr, false);

	bufptr = dlfb_blanking(bufptr, blank_mode);

	bufptr = dlfb_vidreg_unlock(bufptr);



	/* seems like a render op is needed to have blank change take effect */

	bufptr = dlfb_dummy_render(bufptr);



	dlfb_submit_urb(dev, urb, bufptr -

			(char *) urb->transfer_buffer);

	} else {

		dlfb_set_video_mode(dev, &info->var);

	}



	dev->blank_mode = blank_mode;



	return 0;

}

include/video/udlfb.h

+1 −0
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ struct dlfb_data { 
	int base16;

	int base8;

	u32 pseudo_palette[256];

	int blank_mode; /*one of FB_BLANK_ */

	/* blit-only rendering path metrics, exposed through sysfs */

	atomic_t bytes_rendered; /* raw pixel-bytes driver asked to render */

	atomic_t bytes_identical; /* saved effort with backbuffer comparison */