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Revision ab170c27361d1578b4769276ce2bbdb14394743d authored by Ondrej Jirman on 21 April 2018, 04:51:55 UTC, committed by Sean Paul on 25 April 2018, 19:03:12 UTC 
Revert "drm/sun4i: add lvds mode_valid function"
 
The reverted commit broke LVDS output on TBS A711 Tablet. That tablet
has simple-panel node that has fixed pixel clock-frequency that A83T
SoC used in the tablet can't generate exactly.

Requested rate is 52000000 and rounded_rate is calculated as 51857142.
It's close enough for it to work in practice, but with strict check
in the reverted commit, the mode is rejected needlessly in this case.

DT allows to specify a range of values for simple-panel/clock-frequency,
but driver doesn't respect that ATM. Given that TBS A711 is the single
user of sun4i-lvds driver, let's revert that commit for now, until
a better solution for the problem is found.

Also see: https://patchwork.kernel.org/patch/9446385/ for relevant
discussion (or search for "[RFC] drm/sun4i: rgb: Add 5% tolerance
to dot clock frequency check").

Fixes: e4e4b7ad50cf ("drm/sun4i: add lvds mode_valid function")
Reported-by: Ondrej Jirman <megous@megous.com>
Signed-off-by: Ondrej Jirman <megous@megous.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180421045155.15332-1-megous@megous.com
Signed-off-by: Sean Paul <seanpaul@chromium.org>
1 parent 6d08b06
Raw File
dsfield.h 
/* SPDX-License-Identifier: GPL-2.0 */
/* include/net/dsfield.h - Manipulation of the Differentiated Services field */

/* Written 1998-2000 by Werner Almesberger, EPFL ICA */


#ifndef __NET_DSFIELD_H
#define __NET_DSFIELD_H

#include <linux/types.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <asm/byteorder.h>


static inline __u8 ipv4_get_dsfield(const struct iphdr *iph)
{
	return iph->tos;
}


static inline __u8 ipv6_get_dsfield(const struct ipv6hdr *ipv6h)
{
	return ntohs(*(const __be16 *)ipv6h) >> 4;
}


static inline void ipv4_change_dsfield(struct iphdr *iph,__u8 mask,
    __u8 value)
{
        __u32 check = ntohs((__force __be16)iph->check);
	__u8 dsfield;

	dsfield = (iph->tos & mask) | value;
	check += iph->tos;
	if ((check+1) >> 16) check = (check+1) & 0xffff;
	check -= dsfield;
	check += check >> 16; /* adjust carry */
	iph->check = (__force __sum16)htons(check);
	iph->tos = dsfield;
}


static inline void ipv6_change_dsfield(struct ipv6hdr *ipv6h,__u8 mask,
    __u8 value)
{
	__be16 *p = (__force __be16 *)ipv6h;

	*p = (*p & htons((((u16)mask << 4) | 0xf00f))) | htons((u16)value << 4);
}


#endif
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