From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Heiner Kallweit <hkallweit1@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
netdev@vger.kernel.org, Jakub Kicinski <kuba@kernel.org>
Subject: Re: [PATCH net-next] net: sfp: VSOL V2801F / CarlitoxxPro CPGOS03-0490 v2.0 workaround
Date: Tue, 24 Nov 2020 09:43:14 +0000 [thread overview]
Message-ID: <20201124094314.GC1551@shell.armlinux.org.uk> (raw)
In-Reply-To: <20201124002021.GB2031446@lunn.ch>
On Tue, Nov 24, 2020 at 01:20:21AM +0100, Andrew Lunn wrote:
> > @@ -335,10 +336,19 @@ static int sfp_i2c_read(struct sfp *sfp, bool a2, u8 dev_addr, void *buf,
> > size_t len)
> > {
> > struct i2c_msg msgs[2];
> > - u8 bus_addr = a2 ? 0x51 : 0x50;
> > + size_t block_size;
> > size_t this_len;
> > + u8 bus_addr;
> > int ret;
> >
> > + if (a2) {
> > + block_size = 16;
> > + bus_addr = 0x51;
>
> Hi Russell, Thomas
>
> Does this man the diagnostic page can be read 16 bytes at a time, even
> when the other page has to be 1 bytes at a time? That seems rather
> odd. Or is the diagnostic page not implemented in these SFPs?
SFF8472 requires that multibyte values are read using sequential
reads. So we can't use single byte reads to read a multibyte value -
it's just not atomic.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
prev parent reply other threads:[~2020-11-24 9:43 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-23 21:53 [PATCH net-next] net: sfp: VSOL V2801F / CarlitoxxPro CPGOS03-0490 v2.0 workaround Russell King
2020-11-24 0:18 ` kernel test robot
2020-11-25 14:00 ` Russell King - ARM Linux admin
2020-12-02 13:11 ` Russell King - ARM Linux admin
2020-11-24 0:20 ` Andrew Lunn
2020-11-24 9:43 ` Russell King - ARM Linux admin [this message]
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