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Douglas Anderson bfc12020e6 drm/msm/dp: Return IRQ_NONE for unhandled interrupts
If our interrupt handler gets called and we don't really handle the
interrupt then we should return IRQ_NONE. The current interrupt
handler didn't do this, so let's fix it.

NOTE: for some of the cases it's clear that we should return IRQ_NONE
and some cases it's clear that we should return IRQ_HANDLED. However,
there are a few that fall somewhere in between. Specifically, the
documentation for when to return IRQ_NONE vs. IRQ_HANDLED is probably
best spelled out in the commit message of commit d9e4ad5bad ("Document
that IRQ_NONE should be returned when IRQ not actually handled"). That
commit makes it clear that we should return IRQ_HANDLED if we've done
something to make the interrupt stop happening.

The case where it's unclear is, for instance, in dp_aux_isr() after
we've read the interrupt using dp_catalog_aux_get_irq() and confirmed
that "isr" is non-zero. The function dp_catalog_aux_get_irq() not only
reads the interrupts but it also "ack"s all the interrupts that are
returned. For an "unknown" interrupt this has a very good chance of
actually stopping the interrupt from happening. That would mean we've
identified that it's our device and done something to stop them from
happening and should return IRQ_HANDLED. Specifically, it should be
noted that most interrupts that need "ack"ing are ones that are
one-time events and doing an "ack" is enough to clear them. However,
since these interrupts are unknown then, by definition, it's unknown
if "ack"ing them is truly enough to clear them. It's possible that we
also need to remove the original source of the interrupt. In this
case, IRQ_NONE would be a better choice.

Given that returning an occasional IRQ_NONE isn't the absolute end of
the world, however, let's choose that course of action. The IRQ
framework will forgive a few IRQ_NONE returns now and again (and it
won't even log them, which is why we have to log them ourselves). This
means that if we _do_ end hitting an interrupt where "ack"ing isn't
enough the kernel will eventually detect the problem and shut our
device down.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
Reviewed-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/520660/
Link: https://lore.kernel.org/r/20230126170745.v2.2.I2d7aec2fadb9c237cd0090a47d6a8ba2054bf0f8@changeid
[DB: reformatted commit message to make checkpatch happy]
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
2023-04-06 20:29:44 +03:00
arch - Disable XSAVES on AMD Zen1 and Zen2 machines due to an erratum. No 2023-03-12 09:12:03 -07:00
block block, bfq: fix uaf for 'stable_merge_bfqq' 2023-03-08 07:34:50 -07:00
certs Kbuild updates for v6.3 2023-02-26 11:53:25 -08:00
crypto Networking changes for 6.3. 2023-02-21 18:24:12 -08:00
Documentation Merge tag 'dma-fence-deadline' into HEAD 2023-03-28 15:45:53 -07:00
drivers drm/msm/dp: Return IRQ_NONE for unhandled interrupts 2023-04-06 20:29:44 +03:00
fs Fixes for 6.3-rc1: 2023-03-12 09:47:08 -07:00
include drm/msm: Add wait-boost support 2023-03-28 15:46:15 -07:00
init Kbuild updates for v6.3 2023-02-26 11:53:25 -08:00
io_uring io_uring: silence variable ‘prev’ set but not used warning 2023-03-09 10:10:58 -07:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel kernel.fork.v6.3-rc2 2023-03-12 09:04:28 -07:00
lib cpumask: re-introduce constant-sized cpumask optimizations 2023-03-05 14:30:34 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm: avoid gcc complaint about pointer casting 2023-03-04 14:03:27 -08:00
net wifi: cfg80211: Partial revert "wifi: cfg80211: Fix use after free for wext" 2023-03-12 16:21:59 -07:00
rust Rust fixes for 6.3-rc1 2023-03-03 14:51:15 -08:00
samples LoongArch changes for v6.3 2023-03-01 09:27:00 -08:00
scripts Remove Intel compiler support 2023-03-05 10:49:37 -08:00
security capability: just use a 'u64' instead of a 'u32[2]' array 2023-03-01 10:01:22 -08:00
sound sound fixes for 6.3-rc1 2023-03-04 10:53:59 -08:00
tools kernel.fork.v6.3-rc2 2023-03-12 09:04:28 -07:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM/riscv changes for 6.3 2023-02-15 12:33:28 -05:00
.clang-format cpumask: re-introduce constant-sized cpumask optimizations 2023-03-05 14:30:34 -08:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for *.dtso files 2023-02-26 15:28:23 +09:00
.gitignore .gitignore: ignore *.cover and *.mbx 2023-02-05 18:51:22 +09:00
.mailmap drm fixes for 6.3-rc2 2023-03-10 08:57:46 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING
CREDITS There is no particular theme here - mainly quick hits all over the tree. 2023-02-23 17:55:40 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: Update the URI for MSM DRM bugs 2023-03-20 13:58:44 -07:00
Makefile Linux 6.3-rc2 2023-03-12 16:36:44 -07:00
README

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.