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From: Claudiu Beznea <claudiu.beznea@microchip.com>
To: <sam@ravnborg.org>, <bbrezillon@kernel.org>, <airlied@linux.ie>,
	<daniel@ffwll.ch>, <nicolas.ferre@microchip.com>,
	<alexandre.belloni@bootlin.com>,
	<ludovic.desroches@microchip.com>, <lee.jones@linaro.org>
Cc: <dri-devel@lists.freedesktop.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>,
	Claudiu Beznea <claudiu.beznea@microchip.com>,
	Peter Rosin <peda@axentia.se>
Subject: [PATCH 4/5] Revert "drm/atmel-hlcdc: allow selecting a higher pixel-clock than requested"
Date: Tue, 10 Dec 2019 15:24:46 +0200	[thread overview]
Message-ID: <1575984287-26787-5-git-send-email-claudiu.beznea@microchip.com> (raw)
In-Reply-To: <1575984287-26787-1-git-send-email-claudiu.beznea@microchip.com>

This reverts commit f6f7ad3234613f6f7f27c25036aaf078de07e9b0.
("drm/atmel-hlcdc: allow selecting a higher pixel-clock than requested")
because allowing selecting a higher pixel clock may overclock
LCD devices, not all of them being capable of this.

Cc: Peter Rosin <peda@axentia.se>
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
 drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c | 12 ------------
 1 file changed, 12 deletions(-)

diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
index 721fa88bf71d..1a70dff1a417 100644
--- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
+++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
@@ -117,18 +117,6 @@ static void atmel_hlcdc_crtc_mode_set_nofb(struct drm_crtc *c)
 		div = DIV_ROUND_UP(prate, mode_rate);
 		if (ATMEL_HLCDC_CLKDIV(div) & ~ATMEL_HLCDC_CLKDIV_MASK)
 			div = ATMEL_HLCDC_CLKDIV_MASK;
-	} else {
-		int div_low = prate / mode_rate;
-
-		if (div_low >= 2 &&
-		    ((prate / div_low - mode_rate) <
-		     10 * (mode_rate - prate / div)))
-			/*
-			 * At least 10 times better when using a higher
-			 * frequency than requested, instead of a lower.
-			 * So, go with that.
-			 */
-			div = div_low;
 	}
 
 	cfg |= ATMEL_HLCDC_CLKDIV(div);
-- 
2.7.4


  parent reply	other threads:[~2019-12-10 13:25 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-10 13:24 [PATCH 0/5] fixes for atmel-hlcdc Claudiu Beznea
2019-12-10 13:24 ` [PATCH 1/5] drm: atmel-hlcdc: use double rate for pixel clock only if supported Claudiu Beznea
2019-12-10 13:24 ` [PATCH 2/5] drm: atmel-hlcdc: enable clock before configuring timing engine Claudiu Beznea
2019-12-10 20:18   ` Sam Ravnborg
2019-12-10 13:24 ` [PATCH 3/5] mfd: atmel-hlcdc: return in case of error Claudiu Beznea
2019-12-10 20:37   ` Sam Ravnborg
2019-12-11 12:07     ` Claudiu.Beznea
2019-12-10 13:24 ` Claudiu Beznea [this message]
2019-12-10 14:11   ` [PATCH 4/5] Revert "drm/atmel-hlcdc: allow selecting a higher pixel-clock than requested" Peter Rosin
2019-12-10 14:59     ` Claudiu.Beznea
2019-12-10 17:22       ` Peter Rosin
2019-12-11 11:45         ` Claudiu.Beznea
2019-12-11 13:28           ` Peter Rosin
2019-12-13  9:28             ` Claudiu.Beznea
2019-12-13  9:30               ` Peter Rosin
2019-12-10 13:24 ` [PATCH 5/5] Revert "drm: atmel-hlcdc: enable sys_clk during initalization." Claudiu Beznea
2019-12-10 20:34   ` Sam Ravnborg
2019-12-11 11:55     ` Claudiu.Beznea

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