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Damien Le Moal 9c122d020a ata: ahci: Add mask_port_map module parameter 
[ Upstream commit 24cfd86433 ]

Commits 0077a504e1 ("ahci: asm1166: correct count of reported ports")
and 9815e39617 ("ahci: asm1064: correct count of reported ports")
attempted to limit the ports of the ASM1166 and ASM1064 AHCI controllers
to avoid long boot times caused by the fact that these adapters report
a port map larger than the number of physical ports. The excess ports
are "virtual" to hide port multiplier devices and probing these ports
takes time. However, these commits caused a regression for users that do
use PMP devices, as the ATA devices connected to the PMP cannot be
scanned. These commits have thus been reverted by commit 6cd8adc3e1
("ahci: asm1064: asm1166: don't limit reported ports") to allow the
discovery of devices connected through a port multiplier. But this
revert re-introduced the long boot times for users that do not use a
port multiplier setup.

This patch adds the mask_port_map ahci module parameter to allow users
to manually specify port map masks for controllers. In the case of the
ASMedia 1166 and 1064 controllers, users that do not have port
multiplier devices can mask the excess virtual ports exposed by the
controller to speedup port scanning, thus reducing boot time.

The mask_port_map parameter accepts 2 different formats:
 - mask_port_map=<mask>
   This applies the same mask to all AHCI controllers
   present in the system. This format is convenient for small systems
   that have only a single AHCI controller.
 - mask_port_map=<pci_dev>=<mask>,<pci_dev>=mask,...
   This applies the specified masks only to the PCI device listed. The
   <pci_dev> field is a regular PCI device ID (domain🚌dev.func).
   This ID can be seen following "ahci" in the kernel messages. E.g.
   for "ahci 0000:01:00.0: 2/2 ports implemented (port mask 0x3)", the
   <pci_dev> field is "0000:01:00.0".

When used, the function ahci_save_initial_config() indicates that a
port map mask was applied with the message "masking port_map ...".
E.g.: without a mask:
modprobe ahci
dmesg | grep ahci
...
ahci 0000:00:17.0: AHCI vers 0001.0301, 32 command slots, 6 Gbps, SATA mode
ahci 0000:00:17.0: (0000:00:17.0) 8/8 ports implemented (port mask 0xff)

With a mask:
modprobe ahci mask_port_map=0000:00:17.0=0x1
dmesg | grep ahci
...
ahci 0000:00:17.0: masking port_map 0xff -> 0x1
ahci 0000:00:17.0: AHCI vers 0001.0301, 32 command slots, 6 Gbps, SATA mode
ahci 0000:00:17.0: (0000:00:17.0) 1/8 ports implemented (port mask 0x1)

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2024-10-17 15:24:11 +02:00
arch riscv: cpufeature: Fix thead vector hwcap removal 2024-10-17 15:24:11 +02:00
block blk_iocost: fix more out of bound shifts 2024-10-10 11:57:24 +02:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto crypto: simd - Do not call crypto_alloc_tfm during registration 2024-10-10 11:57:26 +02:00
Documentation arm64: errata: Expand speculative SSBS workaround once more 2024-10-10 11:58:02 +02:00
drivers ata: ahci: Add mask_port_map module parameter 2024-10-17 15:24:11 +02:00
fs gfs2: Revert "ignore negated quota changes" 2024-10-17 15:24:08 +02:00
include bus: mhi: ep: Add support for async DMA write operation 2024-10-17 15:24:10 +02:00
init rust: fix the default format for CONFIG_{RUSTC,BINDGEN}_VERSION_TEXT 2024-08-29 17:33:29 +02:00
io_uring io_uring/net: harden multishot termination case for recv 2024-10-10 11:58:02 +02:00
ipc sysctl: treewide: drop unused argument ctl_table_root::set_ownership(table) 2024-08-11 12:47:13 +02:00
kernel tracing: Have saved_cmdlines arrays all in one allocation 2024-10-17 15:24:10 +02:00
lib lib/buildid: harden build ID parsing logic 2024-10-10 11:58:03 +02:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm: z3fold: deprecate CONFIG_Z3FOLD 2024-10-10 11:58:02 +02:00
net libceph: init the cursor when preparing sparse read in msgr2 2024-10-17 15:24:10 +02:00
rust rust: sync: require T: Sync for LockedBy::access 2024-10-10 11:57:44 +02:00
samples samples/bpf: Fix compilation errors with cf-protection option 2024-10-04 16:29:19 +02:00
scripts kconfig: qconf: fix buffer overflow in debug links 2024-10-10 11:58:01 +02:00
security tomoyo: fallback to realpath if symlink's pathname does not exist 2024-10-10 11:57:57 +02:00
sound ALSA: hda/realtek: cs35l41: Fix device ID / model name 2024-10-17 15:24:09 +02:00
tools Revert "perf callchain: Fix stitch LBR memory leaks" 2024-10-10 12:49:09 +02:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt KVM: Use dedicated mutex to protect kvm_usage_count to avoid deadlock 2024-10-04 16:29:47 +02:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Remove *.orig pattern from .gitignore 2024-10-04 16:29:44 +02:00
.mailmap 20 hotfixes. 12 are cc:stable and the remainder address post-6.5 issues 2023-10-24 09:52:16 -10:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
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 membarrier: riscv: Add full memory barrier in switch_mm() 2024-09-12 11:11:45 +02:00
Makefile Linux 6.6.56 2024-10-10 12:50:06 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.