From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?iso-8859-1?Q?M=E5ns_Rullg=E5rd?= Subject: Re: [PATCH 1/2] net: ethernet: nb8800: Do not apply TX delay at MAC level Date: Fri, 04 Nov 2016 15:27:55 +0000 Message-ID: References: <581CA300.1060609@laposte.net> <20161104151151.GF3600@lunn.ch> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT Cc: Sebastian Frias , "David S. Miller" , netdev , LKML , Mason To: Andrew Lunn Return-path: In-Reply-To: <20161104151151.GF3600@lunn.ch> (Andrew Lunn's message of "Fri, 4 Nov 2016 16:11:51 +0100") Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Andrew Lunn writes: > On Fri, Nov 04, 2016 at 04:02:24PM +0100, Sebastian Frias wrote: >> The delay can be applied at PHY or MAC level, but since >> PHY drivers will apply the delay at PHY level when using >> one of the "internal delay" declinations of RGMII mode >> (like PHY_INTERFACE_MODE_RGMII_TXID), applying it again >> at MAC level causes issues. If this is correct, most of the PHY drivers are broken. >> Signed-off-by: Sebastian Frias >> --- >> drivers/net/ethernet/aurora/nb8800.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/net/ethernet/aurora/nb8800.c b/drivers/net/ethernet/aurora/nb8800.c >> index b59aa35..d2855c9 100644 >> --- a/drivers/net/ethernet/aurora/nb8800.c >> +++ b/drivers/net/ethernet/aurora/nb8800.c >> @@ -1282,7 +1282,7 @@ static int nb8800_tangox_init(struct net_device *dev) >> break; >> >> case PHY_INTERFACE_MODE_RGMII_TXID: >> - pad_mode = PAD_MODE_RGMII | PAD_MODE_GTX_CLK_DELAY; >> + pad_mode = PAD_MODE_RGMII; >> break; > > How many boards use this Ethernet driver? How many boards are your > potentially breaking, because they need this delay? > > I guess it is a small number, because doesn't it require the PHY is > also broken, not adding a delay when it should? What if the PHY doesn't have that option? -- Måns Rullgård