| From 51a19d150b520f6cb42143f3bdffacd3c33d7ac5 Mon Sep 17 00:00:00 2001 |
| From: Peter Rosin <peda@axentia.se> |
| Date: Wed, 18 Dec 2019 14:28:28 +0200 |
| Subject: drm: atmel-hlcdc: prefer a lower pixel-clock than requested |
| |
| From: Peter Rosin <peda@axentia.se> |
| |
| commit 51a19d150b520f6cb42143f3bdffacd3c33d7ac5 upstream. |
| |
| 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: 9946a3a9dbed ("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 |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| --- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c |
| +++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c |
| @@ -121,8 +121,8 @@ static void atmel_hlcdc_crtc_mode_set_no |
| 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. |
