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
  ...

1 files changed, 117 insertions, 0 deletions

diff --git a/Documentation/admin-guide/cpu-load.rst b/Documentation/admin-guide/cpu-load.rst
new file mode 100644
index 000000000..21a984337
--- /dev/null
+++ b/Documentation/admin-guide/cpu-load.rst
@@ -0,0 +1,117 @@
+========
+CPU load
+========
+
+Linux exports various bits of information via ``/proc/stat`` and
+``/proc/uptime`` that userland tools, such as top(1), use to calculate
+the average time system spent in a particular state, for example::
+
+    $ iostat
+    Linux 2.6.18.3-exp (linmac)     02/20/2007
+
+    avg-cpu:  %user   %nice %system %iowait  %steal   %idle
+              10.01    0.00    2.92    5.44    0.00   81.63
+
+    ...
+
+Here the system thinks that over the default sampling period the
+system spent 10.01% of the time doing work in user space, 2.92% in the
+kernel, and was overall 81.63% of the time idle.
+
+In most cases the ``/proc/stat``	 information reflects the reality quite
+closely, however due to the nature of how/when the kernel collects
+this data sometimes it can not be trusted at all.
+
+So how is this information collected?  Whenever timer interrupt is
+signalled the kernel looks what kind of task was running at this
+moment and increments the counter that corresponds to this tasks
+kind/state.  The problem with this is that the system could have
+switched between various states multiple times between two timer
+interrupts yet the counter is incremented only for the last state.
+
+
+Example
+-------
+
+If we imagine the system with one task that periodically burns cycles
+in the following manner::
+
+     time line between two timer interrupts
+    |--------------------------------------|
+     ^                                    ^
+     |_ something begins working          |
+                                          |_ something goes to sleep
+                                         (only to be awaken quite soon)
+
+In the above situation the system will be 0% loaded according to the
+``/proc/stat`` (since the timer interrupt will always happen when the
+system is executing the idle handler), but in reality the load is
+closer to 99%.
+
+One can imagine many more situations where this behavior of the kernel
+will lead to quite erratic information inside ``/proc/stat``::
+
+
+	/* gcc -o hog smallhog.c */
+	#include <time.h>
+	#include <limits.h>
+	#include <signal.h>
+	#include <sys/time.h>
+	#define HIST 10
+
+	static volatile sig_atomic_t stop;
+
+	static void sighandler(int signr)
+	{
+		(void) signr;
+		stop = 1;
+	}
+
+	static unsigned long hog (unsigned long niters)
+	{
+		stop = 0;
+		while (!stop && --niters);
+		return niters;
+	}
+
+	int main (void)
+	{
+		int i;
+		struct itimerval it = {
+			.it_interval = { .tv_sec = 0, .tv_usec = 1 },
+			.it_value    = { .tv_sec = 0, .tv_usec = 1 } };
+		sigset_t set;
+		unsigned long v[HIST];
+		double tmp = 0.0;
+		unsigned long n;
+		signal(SIGALRM, &sighandler);
+		setitimer(ITIMER_REAL, &it, NULL);
+
+		hog (ULONG_MAX);
+		for (i = 0; i < HIST; ++i) v[i] = ULONG_MAX - hog(ULONG_MAX);
+		for (i = 0; i < HIST; ++i) tmp += v[i];
+		tmp /= HIST;
+		n = tmp - (tmp / 3.0);
+
+		sigemptyset(&set);
+		sigaddset(&set, SIGALRM);
+
+		for (;;) {
+			hog(n);
+			sigwait(&set, &i);
+		}
+		return 0;
+	}
+
+
+References
+----------
+
+- https://lore.kernel.org/r/loom.20070212T063225-663@post.gmane.org
+- Documentation/filesystems/proc.rst (1.8)
+
+
+Thanks
+------
+
+Con Kolivas, Pavel Machek