| #
342406e4 |
|
09-Apr-2019 |
Lyude Paul <lyude@redhat.com> |
drm/nouveau/i2c: Disable i2c bus access after ->fini()
For a while, we've had the problem of i2c bus access not grabbing
a runtime PM ref when it's being used in userspace by i2c-dev, resulting
in nouveau spamming the kernel log with errors if anything attempts to
access the i2c bus while the GPU is in runtime suspend. An example:
[ 130.078386] nouveau 0000:01:00.0: i2c: aux 000d: begin idle timeout ffffffff
Since the GPU is in runtime suspend, the MMIO region that the i2c bus is
on isn't accessible. On x86, the standard behavior for accessing an
unavailable MMIO region is to just return ~0.
Except, that turned out to be a lie. While computers with a clean
concious will return ~0 in this scenario, some machines will actually
completely hang a CPU on certian bad MMIO accesses. This was witnessed
with someone's Lenovo ThinkPad P50, where sensors-detect attempting to
access the i2c bus while the GPU was suspended would result in a CPU
hang:
CPU: 5 PID: 12438 Comm: sensors-detect Not tainted 5.0.0-0.rc4.git3.1.fc30.x86_64 #1
Hardware name: LENOVO 20EQS64N17/20EQS64N17, BIOS N1EET74W (1.47 ) 11/21/2017
RIP: 0010:ioread32+0x2b/0x30
Code: 81 ff ff ff 03 00 77 20 48 81 ff 00 00 01 00 76 05 0f b7 d7 ed c3
48 c7 c6 e1 0c 36 96 e8 2d ff ff ff b8 ff ff ff ff c3 8b 07 <c3> 0f 1f
40 00 49 89 f0 48 81 fe ff ff 03 00 76 04 40 88 3e c3 48
RSP: 0018:ffffaac3c5007b48 EFLAGS: 00000292 ORIG_RAX: ffffffffffffff13
RAX: 0000000001111000 RBX: 0000000001111000 RCX: 0000043017a97186
RDX: 0000000000000aaa RSI: 0000000000000005 RDI: ffffaac3c400e4e4
RBP: ffff9e6443902c00 R08: ffffaac3c400e4e4 R09: ffffaac3c5007be7
R10: 0000000000000004 R11: 0000000000000001 R12: ffff9e6445dd0000
R13: 000000000000e4e4 R14: 00000000000003c4 R15: 0000000000000000
FS: 00007f253155a740(0000) GS:ffff9e644f600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005630d1500358 CR3: 0000000417c44006 CR4: 00000000003606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
g94_i2c_aux_xfer+0x326/0x850 [nouveau]
nvkm_i2c_aux_i2c_xfer+0x9e/0x140 [nouveau]
__i2c_transfer+0x14b/0x620
i2c_smbus_xfer_emulated+0x159/0x680
? _raw_spin_unlock_irqrestore+0x1/0x60
? rt_mutex_slowlock.constprop.0+0x13d/0x1e0
? __lock_is_held+0x59/0xa0
__i2c_smbus_xfer+0x138/0x5a0
i2c_smbus_xfer+0x4f/0x80
i2cdev_ioctl_smbus+0x162/0x2d0 [i2c_dev]
i2cdev_ioctl+0x1db/0x2c0 [i2c_dev]
do_vfs_ioctl+0x408/0x750
ksys_ioctl+0x5e/0x90
__x64_sys_ioctl+0x16/0x20
do_syscall_64+0x60/0x1e0
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f25317f546b
Code: 0f 1e fa 48 8b 05 1d da 0c 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff
ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01
f0 ff ff 73 01 c3 48 8b 0d ed d9 0c 00 f7 d8 64 89 01 48
RSP: 002b:00007ffc88caab68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00005630d0fe7260 RCX: 00007f25317f546b
RDX: 00005630d1598e80 RSI: 0000000000000720 RDI: 0000000000000003
RBP: 00005630d155b968 R08: 0000000000000001 R09: 00005630d15a1da0
R10: 0000000000000070 R11: 0000000000000246 R12: 00005630d1598e80
R13: 00005630d12f3d28 R14: 0000000000000720 R15: 00005630d12f3ce0
watchdog: BUG: soft lockup - CPU#5 stuck for 23s! [sensors-detect:12438]
Yikes! While I wanted to try to make it so that accessing an i2c bus on
nouveau would wake up the GPU as needed, airlied pointed out that pretty
much any usecase for userspace accessing an i2c bus on a GPU (mainly for
the DDC brightness control that some displays have) is going to only be
useful while there's at least one display enabled on the GPU anyway, and
the GPU never sleeps while there's displays running.
Since teaching the i2c bus to wake up the GPU on userspace accesses is a
good deal more difficult than it might seem, mostly due to the fact that
we have to use the i2c bus during runtime resume of the GPU, we instead
opt for the easiest solution: don't let userspace access i2c busses on
the GPU at all while it's in runtime suspend.
Changes since v1:
* Also disable i2c busses that run over DP AUX
Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
|
| #
b2441318 |
|
01-Nov-2017 |
Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|