This is a note to let you know that I've just added the patch titled
net: sfp: initialize sfp->i2c_block_size at sfp allocation
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-sfp-initialize-sfp-i2c_block_size-at-sfp-allocation.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 813c2dd78618f108fdcf9cd726ea90f081ee2881 Mon Sep 17 00:00:00 2001
From: Ivan Bornyakov <i.bornyakov@xxxxxxxxxxx>
Date: Thu, 6 Apr 2023 16:08:32 +0300
Subject: net: sfp: initialize sfp->i2c_block_size at sfp allocation
From: Ivan Bornyakov <i.bornyakov@xxxxxxxxxxx>
commit 813c2dd78618f108fdcf9cd726ea90f081ee2881 upstream.
sfp->i2c_block_size is initialized at SFP module insertion in
sfp_sm_mod_probe(). Because of that, if SFP module was never inserted
since boot, sfp_read() call will lead to zero-length I2C read attempt,
and not all I2C controllers are happy with zero-length reads.
One way to issue sfp_read() on empty SFP cage is to execute ethtool -m.
If SFP module was never plugged since boot, there will be a zero-length
I2C read attempt.
# ethtool -m xge0
i2c i2c-3: adapter quirk: no zero length (addr 0x0050, size 0, read)
Cannot get Module EEPROM data: Operation not supported
If SFP module was plugged then removed at least once,
sfp->i2c_block_size will be initialized and ethtool -m will fail with
different exit code and without I2C error
# ethtool -m xge0
Cannot get Module EEPROM data: Remote I/O error
Fix this by initializing sfp->i2_block_size at struct sfp allocation
stage so no wild sfp_read() could issue zero-length I2C read.
Signed-off-by: Ivan Bornyakov <i.bornyakov@xxxxxxxxxxx>
Fixes: 0d035bed2a4a ("net: sfp: VSOL V2801F / CarlitoxxPro CPGOS03-0490 v2.0 workaround")
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/phy/sfp.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
--- a/drivers/net/phy/sfp.c
+++ b/drivers/net/phy/sfp.c
@@ -207,6 +207,12 @@ static const enum gpiod_flags gpio_flags
*/
#define SFP_PHY_ADDR 22
+/* SFP_EEPROM_BLOCK_SIZE is the size of data chunk to read the EEPROM
+ * at a time. Some SFP modules and also some Linux I2C drivers do not like
+ * reads longer than 16 bytes.
+ */
+#define SFP_EEPROM_BLOCK_SIZE 16
+
struct sff_data {
unsigned int gpios;
bool (*module_supported)(const struct sfp_eeprom_id *id);
@@ -1754,11 +1760,7 @@ static int sfp_sm_mod_probe(struct sfp *
u8 check;
int ret;
- /* Some SFP modules and also some Linux I2C drivers do not like reads
- * longer than 16 bytes, so read the EEPROM in chunks of 16 bytes at
- * a time.
- */
- sfp->i2c_block_size = 16;
+ sfp->i2c_block_size = SFP_EEPROM_BLOCK_SIZE;
ret = sfp_read(sfp, false, 0, &id.base, sizeof(id.base));
if (ret < 0) {
@@ -2385,6 +2387,7 @@ static struct sfp *sfp_alloc(struct devi
return ERR_PTR(-ENOMEM);
sfp->dev = dev;
+ sfp->i2c_block_size = SFP_EEPROM_BLOCK_SIZE;
mutex_init(&sfp->sm_mutex);
mutex_init(&sfp->st_mutex);
Patches currently in stable-queue which might be from i.bornyakov@xxxxxxxxxxx are
queue-5.10/net-sfp-initialize-sfp-i2c_block_size-at-sfp-allocation.patch
