RE: Bug in drivers/net/ethernet/freescale/fec_main.c, TX is broken. In 4.0.0-rc3

To: Duan Fugang-B38611; netdev@vger.kernel.org; linux-arm-kernel
Subject: Re: Bug in drivers/net/ethernet/freescale/fec_main.c, TX is
broken. In 4.0.0-rc3

Hi!

16.03.2015, 17:01, "fugang.duan@freescale.com"
[off-list ref]:

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 Do you have any lost for reproduce the issue ?

 Current net tree does not have this issue, it works fine. Thanks to

all.

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 From git://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git

 apx@astra:~$ uname -r
 4.0.0-rc3-00150-g10640d3-dirty

I test the commit f00bbd2 that include the patch 2b995f63987.
But cannot reproduce your issue. Pls double confirm it in your board.

Confirmed that net-next is buggy.

Client kernel version:
apx@astra:~$ uname -r
4.0.0-rc3-00875-gf00bbd2-dirty

100M file of zeros on client:
apx@astra:~$ ls -l zeros
-rw-r--r-- 1 apx apx 104857600 мар 10 22:33 zeros

File contents (ran on client host):
apx@astra:~$ hd zeros
00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
|................|
*
06400000

NFS server kernel version:
apx@ct:~$ uname -r
4.0.0-rc2-00480-g29e70e6

100M file of zeros on client:
apx@ct:~$ ls -l zeros
-rw-r--r-- 1 apx apx 104857600 мар 10 22:33 zeros

File contents (ran on server host):
apx@ct:~$ hd zeros
00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
|................|
*
001d4a80  1c f0 9f e5 1c f0 9f e5  1c f0 9f e5 1c f0 9f e5
|................|
*
001d4aa0  1c f0 9f e5 74 fb 00 00  bc ff 93 00 c0 ff 93 00
|....t...........|
001d4ab0  c4 ff 93 00 c8 ff 93 00  cc ff 93 00 d0 ff 93 00
|................|
001d4ac0  d4 ff 93 00 d8 ff 93 00  13 00 00 00 28 63 29 20
|............(c) |
001d4ad0  43 6f 70 79 72 69 67 68  74 20 32 30 30 37 2d 32  |Copyright
2007-2|
001d4ae0  30 31 32 2c 20 46 72 65  65 73 63 61 6c 65 20 53  |012,
Freescale S|
001d4af0  65 6d 69 63 6f 6e 64 75  63 74 6f 72 2e 20 41 6c  |emiconductor.
Al|
001d4b00  6c 20 72 69 67 68 74 73  20 72 65 73 65 72 76 65  |l rights
reserve|
001d4b10  64 2e 00 00 dd 00 2c 41  11 73 00 00 d3 74 00 00
|d.....,A.s...t..|
001d4b20  3d 75 00 00 a9 78 00 00  4f 78 00 00 75 77 00 00
|=u...x..Ox..uw..|
001d4b30  07 76 00 00 c3 79 00 00  09 7a 00 00 75 7a 00 00
|.v...y...z..uz..|

Any other client works fine with this server.
And note that corruption is not random, it looks like a zero page
(vectors at beginning), so somewhere pointer to data is corrupted (and
set to zero(?)).
This is repeated many times.

I use an Embedsky E9 board:
http://en.embedsky.com/product_info.php?cateid=169&id=169
It is SabreSD-alike board with a fewer peripherials, and at network side
it has a different PHY, instead of Atheros it has a Realtek RTL8211E, and
I have to initialize it this way (board early fixup patch):

--- a/arch/arm/mach-imx/mach-imx6q.c
+++ b/arch/arm/mach-imx/mach-imx6q.c

@@ -166,6 +166,19 @@ static int ar8035_phy_fixup(struct phy_device *dev)

 #define PHY_ID_AR8035 0x004dd072

+static int rtl8211e_phy_fixup(struct phy_device *dev) {
+       phy_write(dev, 0x00, 0x3140);
+       msleep(10);
+       phy_write(dev, 0x00, 0x3340);
+       msleep(10);
+
+       return 0;
+}
+
+#define PHY_ID_RTL8211E 0x001cc915
+#define REALTEK_PHY_ID_MASK 0x001fffff
+
 static void __init imx6q_enet_phy_init(void)  {
        if (IS_BUILTIN(CONFIG_PHYLIB)) { @@ -177,6 +190,8 @@ static void

__init imx6q_enet_phy_init(void)
                                ar8031_phy_fixup);
                phy_register_fixup_for_uid(PHY_ID_AR8035, 0xffffffef,
                                ar8035_phy_fixup);
+               phy_register_fixup_for_uid(PHY_ID_RTL8211E,
REALTEK_PHY_ID_MASK,
+                               rtl8211e_phy_fixup);
        }
 }

(LAKML folks told me this should go somewhere in network driver, but now
it is there)

Without this there is no network at all, and I had ran this code for year
without any glitch. 3.19 kernel works fine.
(It causes "-dirty" in kernel version)
And different phy initialization cannot cause a non-random stream
corruption.

I've found commit that produces a bug by looking a changes between 3.19
(surely working)  and 4.0.0-rc3 (surely non-working) in freescale network
driver.

Hope this helps.

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