viafb: fix OLPC DCON refresh rate (b4ce6a28) · Commits · 戴 / test

This patch fixes a regression introduced by "viafb: remove duplicated clock storage" caused by an incosistent mode which pretended to have a higher refresh rate than it actually had. The wrong refresh rate resulted in a calculated higher pixclock which the OLPC DCON could not handle. By reducing the refresh rate to 50Hz we get close to the old pixclock which makes the OLPC display usable again. Minor other adjustments are needed as 60Hz is assumed to be a safe value which is not true for OLPC DCON. This is no problem as we only support 1200x900 on the OLPC. Signed-off-by:

Florian Tobias Schandinat <FlorianSchandinat@gmx.de> Reported-by:

Daniel Drake <dsd@laptop.org>

drivers/video/via/hw.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -2598,8 +2598,12 @@ int viafb_get_refresh(int hres, int vres, u32 long_refresh)
		best = &vmode->crtc[i];
		}

		if (abs(best->refresh_rate - long_refresh) > 3)
		if (abs(best->refresh_rate - long_refresh) > 3) {
		if (hres == 1200 && vres == 900)
		return 50; /* OLPC DCON only supports 50 Hz */
		else
		return 60;
		}

		return best->refresh_rate;
		}

drivers/video/via/viamode.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -606,7 +606,7 @@ static struct crt_mode_table CRTM1200x720[] = {
		/* 1200x900 (DCON) */
		static struct crt_mode_table DCON1200x900[] = {
		/* r_rate, hsp, vsp */
		{REFRESH_60, M1200X900_R60_HSP, M1200X900_R60_VSP,
		{REFRESH_50, M1200X900_R60_HSP, M1200X900_R60_VSP,
		/* The correct htotal is 1240, but this doesn't raster on VX855. */
		/* Via suggested changing to a multiple of 16, hence 1264. */
		/* HT, HA, HBS, HBE, HSS, HSE, VT, VA, VBS, VBE, VSS, VSE */

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