Bug 216320 - KSZ8794 operation broken
Summary: KSZ8794 operation broken
Status: NEW
Alias: None
Product: Drivers
Classification: Unclassified
Component: Network (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: drivers_network@kernel-bugs.osdl.org
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2022-08-03 00:24 UTC by Craig McQueen
Modified: 2022-08-17 14:19 UTC (History)
1 user (show)

See Also:
Kernel Version: 5.15
Tree: Mainline
Regression: No


Attachments
keep compatibility with device tree blobs with no phy-mode (2.45 KB, application/mbox)
2022-08-17 14:17 UTC, Vladimir Oltean
Details

Description Craig McQueen 2022-08-03 00:24:12 UTC
After upgrading a Yocto build system from kernel 5.4 to 5.15, I found KSZ8794 switch operation was no longer functional. I got errors such as:

Aug  1 22:23:17 tv999996 kern.err kernel: [   10.770912] ksz8795-switch spi2.0: Unsupported interface: gmii, port: 0
Aug  1 22:23:17 tv999996 kern.warn kernel: [   10.777562] ksz8795-switch spi2.0 wan (uninitialized): validation of gmii with support 0000000,00000000,000062cf and advertisement 0000000,00000000,000062cf failed: -22
Aug  1 22:23:17 tv999996 kern.err kernel: [   10.792874] ksz8795-switch spi2.0 wan (uninitialized): failed to connect to PHY: -EINVAL
Aug  1 22:23:17 tv999996 kern.err kernel: [   10.800978] ksz8795-switch spi2.0 wan (uninitialized): error -22 setting up PHY for tree 0, switch 0, port 0
Aug  1 22:23:17 tv999996 kern.err kernel: [   10.829188] ksz8795-switch spi2.0: Unsupported interface: gmii, port: 1
Aug  1 22:23:17 tv999996 kern.warn kernel: [   10.835821] ksz8795-switch spi2.0 lan2 (uninitialized): validation of gmii with support 0000000,00000000,000062cf and advertisement 0000000,00000000,000062cf failed: -22
Aug  1 22:23:17 tv999996 kern.err kernel: [   10.851156] ksz8795-switch spi2.0 lan2 (uninitialized): failed to connect to PHY: -EINVAL
Aug  1 22:23:17 tv999996 kern.err kernel: [   10.859358] ksz8795-switch spi2.0 lan2 (uninitialized): error -22 setting up PHY for tree 0, switch 0, port 1
Aug  1 22:23:17 tv999996 kern.err kernel: [   10.892821] ksz8795-switch spi2.0: Unsupported interface: gmii, port: 2
Aug  1 22:23:17 tv999996 kern.warn kernel: [   10.899466] ksz8795-switch spi2.0 lan1 (uninitialized): validation of gmii with support 0000000,00000000,000062cf and advertisement 0000000,00000000,000062cf failed: -22
Aug  1 22:23:17 tv999996 kern.err kernel: [   10.914845] ksz8795-switch spi2.0 lan1 (uninitialized): failed to connect to PHY: -EINVAL
Aug  1 22:23:17 tv999996 kern.err kernel: [   10.923052] ksz8795-switch spi2.0 lan1 (uninitialized): error -22 setting up PHY for tree 0, switch 0, port 2

I found that if I reverted commit 2c709e0bdad4d996ec8925b9ee6d5b97458708f1, "net: dsa: microchip: ksz8795: add phylink support", then it worked properly again. The errors I saw were due to the checks in ksz8_validate() that were added in the above commit.
Comment 1 Vladimir Oltean 2022-08-17 14:17:57 UTC
Created attachment 301595 [details]
keep compatibility with device tree blobs with no phy-mode
Comment 2 Vladimir Oltean 2022-08-17 14:19:19 UTC
Hi Craig, I've attached a patch formatted against linux-5.15.y. Can you please confirm that it fixes the problem? The code has changed in the current "net" git tree, so if this works, I'll need to submit a different patch for the current trees, and take care of backporting separately.

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