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Jiaxun Yang 6f709907ea PCI: loongson: Limit MRRS to 256
commit ef61a04057 upstream.

This is a partial revert of 8b3517f88f ("PCI: loongson: Prevent LS7A MRRS
increases") for MIPS-based Loongson.

Some MIPS Loongson systems don't support arbitrary Max_Read_Request_Size
(MRRS) settings.  8b3517f88f ("PCI: loongson: Prevent LS7A MRRS
increases") worked around that by (1) assuming that firmware configured
MRRS to the maximum supported value and (2) preventing the PCI core from
increasing MRRS.

Unfortunately, some firmware doesn't set that maximum MRRS correctly, which
results in devices not being initialized correctly.  One symptom, from the
Debian report below, is this:

  ata4.00: exception Emask 0x0 SAct 0x20000000 SErr 0x0 action 0x6 frozen
  ata4.00: failed command: WRITE FPDMA QUEUED
  ata4.00: cmd 61/20:e8:00:f0:e1/00:00:00:00:00/40 tag 29 ncq dma 16384 out
           res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
  ata4.00: status: { DRDY }
  ata4: hard resetting link

Limit MRRS to 256 because MIPS Loongson with higher MRRS support is
considered rare.

This must be done at device enablement stage because the MRRS setting may
get lost if PCI_COMMAND_MASTER on the parent bridge is cleared, and we are
only sure parent bridge is enabled at this point.

Fixes: 8b3517f88f ("PCI: loongson: Prevent LS7A MRRS increases")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217680
Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1035587
Link: https://lore.kernel.org/r/20231201115028.84351-1-jiaxun.yang@flygoat.com
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Huacai Chen <chenhuacai@loongson.cn>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-20 15:17:38 +01:00
arch MIPS: Loongson64: Handle more memory types passed from firmware 2023-12-20 15:17:33 +01:00
block blk-core: use pr_warn_ratelimited() in bio_check_ro() 2023-11-20 11:08:29 +01:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:22:01 +02:00
crypto crypto: pcrypt - Fix hungtask for PADATA_RESET 2023-11-28 16:56:18 +00:00
Documentation docs/process/howto: Replace C89 with C11 2023-12-13 18:36:46 +01:00
drivers PCI: loongson: Limit MRRS to 256 2023-12-20 15:17:38 +01:00
fs fuse: dax: set fc->dax to NULL in fuse_dax_conn_free() 2023-12-20 15:17:38 +01:00
include cred: switch to using atomic_long_t 2023-12-20 15:17:37 +01:00
init proc: sysctl: prevent aliased sysctls from getting passed to init 2023-12-03 07:31:24 +01:00
io_uring io_uring/af_unix: disable sending io_uring over sockets 2023-12-13 18:36:46 +01:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:28:45 +01:00
kernel cred: switch to using atomic_long_t 2023-12-20 15:17:37 +01:00
lib parisc: Drop the HP-UX ENOSYM and EREMOTERELEASE error codes 2023-12-08 08:48:02 +01:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm memblock: allow to specify flags with memblock_add_node() 2023-12-20 15:17:33 +01:00
net appletalk: Fix Use-After-Free in atalk_ioctl 2023-12-20 15:17:37 +01:00
samples samples/hw_breakpoint: fix building without module unloading 2023-09-23 11:10:01 +02:00
scripts sign-file: Fix incorrect return values check 2023-12-20 15:17:37 +01:00
security KEYS: trusted: Rollback init_trusted() consistently 2023-11-28 16:56:30 +00:00
sound ALSA: hda/realtek: Apply mute LED quirk for HP15-db 2023-12-20 15:17:38 +01:00
tools tools headers UAPI: Sync linux/perf_event.h with the kernel sources 2023-12-13 18:36:46 +01:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt KVM: Grab a reference to KVM for VM and vCPU stats file descriptors 2023-08-03 10:22:40 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS iio: stx104: Move to addac subdirectory 2023-08-26 14:23:27 +02:00
Makefile Linux 5.15.143 2023-12-13 18:36:50 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.