Commit 51a19d15 authored Dec 18, 2019 by Peter Rosin Committed by Sam Ravnborg Jan 06, 2020

drm: atmel-hlcdc: prefer a lower pixel-clock than requested

The intention was to only select a higher pixel-clock rate than the
requested, if a slight overclocking would result in a rate significantly
closer to the requested rate than if the conservative lower pixel-clock
rate is selected. The fixed patch has the logic the other way around and
actually prefers the higher frequency. Fix that.

Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Fixes: 9946a3a9 ("drm/atmel-hlcdc: allow selecting a higher pixel-clock than requested")
Reported-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Tested-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Cc: Boris Brezillon <boris.brezillon@bootlin.com>
Cc: <stable@vger.kernel.org> # v4.20+
Link: https://patchwork.freedesktop.org/patch/msgid/1576672109-22707-6-git-send-email-claudiu.beznea@microchip.com

parent 2c1fb9d8

drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -121,8 +121,8 @@ static void atmel_hlcdc_crtc_mode_set_nofb(struct drm_crtc *c)
		int div_low = prate / mode_rate;

		if (div_low >= 2 &&
		((prate / div_low - mode_rate) <
		10 * (mode_rate - prate / div)))
		(10 * (prate / div_low - mode_rate) <
		(mode_rate - prate / div)))
		/*
		* At least 10 times better when using a higher
		* frequency than requested, instead of a lower.