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commitfc0649395dupstream. Fix an issue where the kernel would stall during netboot, showing the "sched: RT throttling activated" message. This stall was triggered by the behavior of the mii_interrupt bit (Bit 7 - DP83TD510E_STS_MII_INT) in the DP83TD510E's PHY_STS Register (Address = 0x10). The DP83TD510E datasheet (2020) states that the bit clears on write, however, in practice, the bit clears on read. This discrepancy had significant implications on the driver's interrupt handling. The PHY_STS Register was used by handle_interrupt() to check for pending interrupts and by read_status() to get the current link status. The call to read_status() was unintentionally clearing the mii_interrupt status bit without deasserting the IRQ pin, causing handle_interrupt() to miss other pending interrupts. This issue was most apparent during netboot. The fix refrains from using the PHY_STS Register for interrupt handling. Instead, we now solely rely on the INTERRUPT_REG_1 Register (Address = 0x12) and INTERRUPT_REG_2 Register (Address = 0x13) for this purpose. These registers directly influence the IRQ pin state and are latched high until read. Note: The INTERRUPT_REG_2 Register (Address = 0x13) exists and can also be used for interrupt handling, specifically for "Aneg page received interrupt" and "Polarity change interrupt". However, these features are currently not supported by this driver. Fixes:165cd04fe2("net: phy: dp83td510: Add support for the DP83TD510 Ethernet PHY") Cc: <stable@vger.kernel.org> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Link: https://lore.kernel.org/r/20230621043848.3806124-1-o.rempel@pengutronix.de Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.