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From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Marcin Wojtas <mw@semihalf.com>
Cc: Stefan Chulski <stefanc@marvell.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: mvpp2: incorrect max mtu?
Date: Fri, 14 May 2021 18:19:45 +0100	[thread overview]
Message-ID: <20210514171945.GF12395@shell.armlinux.org.uk> (raw)
In-Reply-To: <CAPv3WKcRpk+7y_TN1dsSE0rS90vTk5opU59i5=4=XP-805axfQ@mail.gmail.com>

On Fri, May 14, 2021 at 04:25:48PM +0200, Marcin Wojtas wrote:
> Thank your for the information. I will take a look after the weekend.
> To be aligned - what exactly kernel baseline are you using?

That was with 5.11 with these additional mvpp2 patches:

net: mvpp2: add TX FC firmware check
net: mvpp2: set 802.3x GoP Flow Control mode
net: mvpp2: add PPv23 RX FIFO flow control
net: mvpp2: add BM protection underrun feature support
net: mvpp2: add ethtool flow control configuration support
net: mvpp2: add RXQ flow control configurations
net: mvpp2: enable global flow control
net: mvpp2: add FCA RXQ non occupied descriptor threshold
net: mvpp2: add FCA periodic timer configurations
net: mvpp2: increase BM pool and RXQ size
net: mvpp2: add PPv23 version definition
net: mvpp2: always compare hw-version vs MVPP21
net: mvpp2: add CM3 SRAM memory map
dts: marvell: add CM3 SRAM memory to cp11x ethernet device tree
doc: marvell: add CM3 address space and PPv2.3 description
net: marvell: Fixed two spellings,controling to controlling and oen to one
net: mvpp2: prs: improve ipv4 parse flow

I'll also try to work out what's happening, but I think we need to find
out what the correct value for dev->max_mtu should be. That's all rather
convoluted:

	dev->max_mtu = MVPP2_BM_JUMBO_PKT_SIZE;

#define MVPP2_BM_JUMBO_PKT_SIZE MVPP2_RX_MAX_PKT_SIZE(MVPP2_BM_JUMBO_FRAME_SIZE)
#define MVPP2_BM_JUMBO_FRAME_SIZE       10432   /* frame size 9856 */
#define MVPP2_RX_MAX_PKT_SIZE(total_size) \
        ((total_size) - MVPP2_SKB_HEADROOM - MVPP2_SKB_SHINFO_SIZE)

The maximum settable MTU on eth0 (9888) disagrees with the comment
"frame size 9856" by 32 bytes.

I haven't checked to see whether 9856 works yet, because that will
first need me to reboot the machine... which I'll do over the weekend.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!

  reply	other threads:[~2021-05-14 17:19 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-14 13:00 mvpp2: incorrect max mtu? Russell King (Oracle)
2021-05-14 14:25 ` Marcin Wojtas
2021-05-14 17:19   ` Russell King (Oracle) [this message]
2021-05-14 14:35 ` Andrew Lunn
2021-05-14 17:21   ` Russell King (Oracle)
2021-05-18  6:09 ` [EXT] " Stefan Chulski
2021-05-18  9:41   ` Russell King (Oracle)
2021-05-18 10:25     ` Stefan Chulski
2021-05-23 10:54       ` Stefan Chulski

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