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A mirror of the official Linux kernel repository just in case
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Kernel messages produced during runtime PM can cause a never-ending cycle because user space utilities (e.g. journald or rsyslog) write the messages back to storage, causing runtime resume, more messages, and so on. Messages that tell of things that are expected to happen, are arguably unnecessary, so suppress them. UFS driver messages are changes to from dev_err() to dev_dbg() which means they will not display unless activated by dynamic debug of building with -DDEBUG. sdev->silence_suspend is set to skip messages from sd_suspend_common() "Synchronizing SCSI cache", "Stopping disk" and scsi_report_sense() "Power-on or device reset occurred" message (Note, that message appears when the LUN is accessed after runtime PM, not during runtime PM) Example messages from Ubuntu 21.10: $ dmesg | tail [ 1620.380071] ufshcd 0000:00:12.5: ufshcd_print_pwr_info:[RX, TX]: gear=[1, 1], lane[1, 1], pwr[SLOWAUTO_MODE, SLOWAUTO_MODE], rate = 0 [ 1620.408825] ufshcd 0000:00:12.5: ufshcd_print_pwr_info:[RX, TX]: gear=[4, 4], lane[2, 2], pwr[FAST MODE, FAST MODE], rate = 2 [ 1620.409020] ufshcd 0000:00:12.5: ufshcd_find_max_sup_active_icc_level: Regulator capability was not set, actvIccLevel=0 [ 1620.409524] sd 0:0:0:0: Power-on or device reset occurred [ 1622.938794] sd 0:0:0:0: [sda] Synchronizing SCSI cache [ 1622.939184] ufs_device_wlun 0:0:0:49488: Power-on or device reset occurred [ 1625.183175] ufshcd 0000:00:12.5: ufshcd_print_pwr_info:[RX, TX]: gear=[1, 1], lane[1, 1], pwr[SLOWAUTO_MODE, SLOWAUTO_MODE], rate = 0 [ 1625.208041] ufshcd 0000:00:12.5: ufshcd_print_pwr_info:[RX, TX]: gear=[4, 4], lane[2, 2], pwr[FAST MODE, FAST MODE], rate = 2 [ 1625.208311] ufshcd 0000:00:12.5: ufshcd_find_max_sup_active_icc_level: Regulator capability was not set, actvIccLevel=0 [ 1625.209035] sd 0:0:0:0: Power-on or device reset occurred Note for stable: depends on patch "scsi: core: sd: Add silence_suspend flag to suppress some PM messages". Link: https://lore.kernel.org/r/20220228113652.970857-3-adrian.hunter@intel.com Cc: stable@vger.kernel.org Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> |
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| certs | ||
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| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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.