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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-19 10:09:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-19 10:09:22 -0700
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Merge tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-mediagrafted
Pull media updates from Mauro Carvalho Chehab: - v4l2-core: added ISP statistics support and per-block validation - v4l2-core: Allow unknown HDR10 white point and luminance - New camera sensors: Sony IMX678 and IMX471m, Himax HM1092 IR sensor - New codec: Milos: VPU v2.0 codec support - isp driver: gained support for Dreamchip RPPX1 ISP framework - vsp1 driver: gained support for RZ/T2H and RZ/N2H - Novalake driver: gained CVS support for new NVL hardware - dvb-core: fix feed leak on failed DMX_ADD_PID - several driver fixes, cleanups and minor improvements * tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (308 commits) media: ipu-bridge: check all DMI entries when overriding sensor rotation media: v4l2-async: avoid deleting unlinked ASC entry on link error media: rzg2l-cru: Align bytesperline to hardware DMA stride requirement media: intel/ipu6: fix async notifier cleanup leak on parse error media: staging/ipu7: fix async notifier UAF on probe error path media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path media: amd: isp4: release partial allocations in isp4if_alloc_fw_gpumem() media: rcar-isp: Fix VSPX reference leaks media: rcar-isp: Release ISPCORE resources media: i2c: imx415: Release runtime PM reference on VBLANK error media: i2c: imx415: Return test pattern write errors media: renesas: vsp1: Declare index variables in for loop statement media: renesas: vsp1: Make reset control optional to support platforms without a reset line media: dt-bindings: media: renesas,vsp1: Document RZ/T2H and RZ/N2H SoCs media: dt-bindings: media: renesas,fcp: Document RZ/T2H and RZ/N2H SoCs media: nxp: imx8-isi: Add additional 32-bit RGB format support media: nxp: imx8-isi: Add 16-bit raw Bayer format support media: nxp: imx8-isi: Implement per-stream reference counting for multiplexed streams media: nxp: imx8-isi: Use BIT_ULL() for 64-bit stream masks media: nxp: imx8-isi: Correct color map between V4L2 and ISI ...
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+.. SPDX-License-Identifier: GPL-2.0
+
+===============
+NETIF Msg Level
+===============
+
+The design of the network interface message level setting.
+
+History
+-------
+
+ The design of the debugging message interface was guided and
+ constrained by backwards compatibility previous practice. It is useful
+ to understand the history and evolution in order to understand current
+ practice and relate it to older driver source code.
+
+ From the beginning of Linux, each network device driver has had a local
+ integer variable that controls the debug message level. The message
+ level ranged from 0 to 7, and monotonically increased in verbosity.
+
+ The message level was not precisely defined past level 3, but were
+ always implemented within +-1 of the specified level. Drivers tended
+ to shed the more verbose level messages as they matured.
+
+ - 0 Minimal messages, only essential information on fatal errors.
+ - 1 Standard messages, initialization status. No run-time messages
+ - 2 Special media selection messages, generally timer-driver.
+ - 3 Interface starts and stops, including normal status messages
+ - 4 Tx and Rx frame error messages, and abnormal driver operation
+ - 5 Tx packet queue information, interrupt events.
+ - 6 Status on each completed Tx packet and received Rx packets
+ - 7 Initial contents of Tx and Rx packets
+
+ Initially this message level variable was uniquely named in each driver
+ e.g. "lance_debug", so that a kernel symbolic debugger could locate and
+ modify the setting. When kernel modules became common, the variables
+ were consistently renamed to "debug" and allowed to be set as a module
+ parameter.
+
+ This approach worked well. However there is always a demand for
+ additional features. Over the years the following emerged as
+ reasonable and easily implemented enhancements
+
+ - Using an ioctl() call to modify the level.
+ - Per-interface rather than per-driver message level setting.
+ - More selective control over the type of messages emitted.
+
+ The netif_msg recommendation adds these features with only a minor
+ complexity and code size increase.
+
+ The recommendation is the following points
+
+ - Retaining the per-driver integer variable "debug" as a module
+ parameter with a default level of '1'.
+
+ - Adding a per-interface private variable named "msg_enable". The
+ variable is a bit map rather than a level, and is initialized as::
+
+ 1 << debug
+
+ Or more precisely::
+
+ debug < 0 ? 0 : 1 << min(sizeof(int)-1, debug)
+
+ Messages should changes from::
+
+ if (debug > 1)
+ printk(MSG_DEBUG "%s: ...
+
+ to::
+
+ if (np->msg_enable & NETIF_MSG_LINK)
+ printk(MSG_DEBUG "%s: ...
+
+
+The set of message levels is named
+
+
+ ========= =================== ============
+ Old level Name Bit position
+ ========= =================== ============
+ 0 NETIF_MSG_DRV 0x0001
+ 1 NETIF_MSG_PROBE 0x0002
+ 2 NETIF_MSG_LINK 0x0004
+ 2 NETIF_MSG_TIMER 0x0004
+ 3 NETIF_MSG_IFDOWN 0x0008
+ 3 NETIF_MSG_IFUP 0x0008
+ 4 NETIF_MSG_RX_ERR 0x0010
+ 4 NETIF_MSG_TX_ERR 0x0010
+ 5 NETIF_MSG_TX_QUEUED 0x0020
+ 5 NETIF_MSG_INTR 0x0020
+ 6 NETIF_MSG_TX_DONE 0x0040
+ 6 NETIF_MSG_RX_STATUS 0x0040
+ 7 NETIF_MSG_PKTDATA 0x0080
+ ========= =================== ============