Introduce sysfs interfaces for 3 new Data Streaming Accelerator (DSA)
capability registers (dsacap0-2) to enable userspace awareness of hardware
features in DSA version 3 and later devices.
Userspace components (e.g. configure libraries, workload Apps) require this
information to:
1. Select optimal data transfer strategies based on SGL capabilities
2. Enable hardware-specific optimizations for floating-point operations
3. Configure memory operations with proper numerical handling
4. Verify compute operation compatibility before submitting jobs
The output format is <dsacap2>,<dsacap1>,<dsacap0>, where each DSA
capability value is a 64-bit hexadecimal number, separated by commas.
The ordering follows the DSA 3.0 specification layout:
Offset: 0x190 0x188 0x180
Reg: dsacap2 dsacap1 dsacap0
Example:
cat /sys/bus/dsa/devices/dsa0/dsacaps
000000000000f18d,0014000e000007aa,00fa01ff01ff03ff
According to the DSA 3.0 specification, there are 15 fields defined for
the three dsacap registers. However, there's no need to define all
register structures unless a use case requires them. At this point,
support for the Scatter-Gather List (SGL) located in dsacap0 is necessary,
so only dsacap0 is defined accordingly.
For reference, the DSA 3.0 specification is available at:
Link: https://software.intel.com/content/www/us/en/develop/articles/intel-data-streaming-accelerator-architecture-specification.html
Signed-off-by: Yi Sun <yi.sun@intel.com>
Co-developed-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Tested-by: Yi Lai <yi1.lai@intel.com>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Link: https://patch.msgid.link/20260107-idxd-yi-sun-dsa3-sgl-size-v2-1-dbef8f559e48@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Add the idxd_pci_probe_alloc() helper to probe IDXD PCI device with or
without allocating and setting idxd software values.
The idxd_pci_probe() function is refactored to call this helper and
always probe the IDXD device with allocating and setting the software
values.
This helper will be called later in the Function Level Reset (FLR)
process without modifying the idxd software data.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20241122233028.2762809-2-fenghua.yu@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
On Sapphire Rapids and related platforms, the DSA and IAA devices have an
erratum that causes direct access (for example, by using the ENQCMD or
MOVDIR64 instructions) from untrusted applications to be a security problem.
To solve this, add a flag to the PCI device enumeration and device structures
to indicate the presence/absence of this security exposure. In the mmap()
method of the device, this flag is then used to enforce that the user
has the CAP_SYS_RAWIO capability.
In a future patch, a write() based method will be added that allows untrusted
applications submit work to the accelerator, where the kernel can do
sanity checking on the user input to ensure secure operation of the accelerator.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
drain_workqueue() cannot be called safely in a spinlocked context due to
possible task rescheduling. In the multi-task scenario, calling
queue_work() while drain_workqueue() will lead to a Call Trace as
pushing a work on a draining workqueue is not permitted in spinlocked
context.
Call Trace:
<TASK>
? __warn+0x7d/0x140
? __queue_work+0x2b2/0x440
? report_bug+0x1f8/0x200
? handle_bug+0x3c/0x70
? exc_invalid_op+0x18/0x70
? asm_exc_invalid_op+0x1a/0x20
? __queue_work+0x2b2/0x440
queue_work_on+0x28/0x30
idxd_misc_thread+0x303/0x5a0 [idxd]
? __schedule+0x369/0xb40
? __pfx_irq_thread_fn+0x10/0x10
? irq_thread+0xbc/0x1b0
irq_thread_fn+0x21/0x70
irq_thread+0x102/0x1b0
? preempt_count_add+0x74/0xa0
? __pfx_irq_thread_dtor+0x10/0x10
? __pfx_irq_thread+0x10/0x10
kthread+0x103/0x140
? __pfx_kthread+0x10/0x10
ret_from_fork+0x31/0x50
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1b/0x30
</TASK>
The current implementation uses a spinlock to protect event log workqueue
and will lead to the Call Trace due to potential task rescheduling.
To address the locking issue, convert the spinlock to mutex, allowing
the drain_workqueue() to be called in a safe mutex-locked context.
This change ensures proper synchronization when accessing the event log
workqueue, preventing potential Call Trace and improving the overall
robustness of the code.
Fixes: c40bd7d973 ("dmaengine: idxd: process user page faults for completion record")
Signed-off-by: Rex Zhang <rex.zhang@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Lijun Pan <lijun.pan@intel.com>
Link: https://lore.kernel.org/r/20240404223949.2885604-1-fenghua.yu@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Pull dmaengine updates from Vinod Koul:
"New hardware support:
- Allwinner H616 dma support
- Renesas r8a779h0 dma controller support
- TI CSI2RX dma support
Updates:
- Freescale edma driver updates for TCD64csupport for i.MX95
- constify of pointers and args
- Yaml conversion for MediaTek High-Speed controller binding
- TI k3 udma support for TX/RX DMA channels for thread IDs:
* tag 'dmaengine-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine: (25 commits)
dmaengine: of: constify of_phandle_args in of_dma_find_controller()
dmaengine: pl08x: constify pointer to char in filter function
MAINTAINERS: change in AMD ptdma maintainer
MAINTAINERS: adjust file entry in MEDIATEK DMA DRIVER
dmaengine: idxd: constify the struct device_type usage
dt-bindings: renesas,rcar-dmac: Add r8a779h0 support
dt-bindings: dma: convert MediaTek High-Speed controller to the json-schema
dmaengine: idxd: make dsa_bus_type const
dmaengine: fsl-edma: integrate TCD64 support for i.MX95
dt-bindings: fsl-dma: fsl-edma: add fsl,imx95-edma5 compatible string
dmaengine: mcf-edma: utilize edma_write_tcdreg() macro for TCD Access
dmaengine: fsl-edma: add address for channel mux register in fsl_edma_chan
dmaengine: fsl-edma: fix spare build warning
dmaengine: fsl-edma: involve help macro fsl_edma_set(get)_tcd()
dt-bindings: mmp-dma: convert to YAML
dmaengine: ti: k3-psil-j721s2: Add entry for CSI2RX
dmaengine: ti: k3-udma-glue: Add function to request RX chan for thread ID
dmaengine: ti: k3-udma-glue: Add function to request TX chan for thread ID
dmaengine: ti: k3-udma-glue: Update name for remote RX channel device
dmaengine: ti: k3-udma-glue: Add function to parse channel by ID
...
head is defined in idxd->evl as a shadow of head in the EVLSTATUS register.
There are two issues related to the shadow head:
1. Mismatch between the shadow head and the state of the EVLSTATUS
register:
If Event Log is supported, upon completion of the Enable Device command,
the Event Log head in the variable idxd->evl->head should be cleared to
match the state of the EVLSTATUS register. But the variable is not reset
currently, leading mismatch between the variable and the register state.
The mismatch causes incorrect processing of Event Log entries.
2. Unnecessary shadow head definition:
The shadow head is unnecessary as head can be read directly from the
EVLSTATUS register. Reading head from the register incurs no additional
cost because event log head and tail are always read together and
tail is already read directly from the register as required by hardware.
Remove the shadow Event Log head stored in idxd->evl to address the
mentioned issues.
Fixes: 244da66cda ("dmaengine: idxd: setup event log configuration")
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20240215024931.1739621-1-fenghua.yu@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Add a load_device_defaults() function pointer to struct
idxd_driver_data, which if defined, will be called when an idxd device
is probed and will allow the idxd device to be configured with default
values.
The load_device_defaults() function is passed an idxd device to work
with to set specific device attributes.
Also add a load_device_defaults() implementation IAA devices; future
patches would add default functions for other device types such as
DSA.
The way idxd device probing works, if the device configuration is
valid at that point e.g. at least one workqueue and engine is properly
configured then the device will be enabled and ready to go.
The IAA implementation, idxd_load_iaa_device_defaults(), configures a
single workqueue (wq0) for each device with the following default
values:
mode "dedicated"
threshold 0
size Total WQ Size from WQCAP
priority 10
type IDXD_WQT_KERNEL
group 0
name "iaa_crypto"
driver_name "crypto"
Note that this now adds another configuration step for any users that
want to configure their own devices/workqueus with something different
in that they'll first need to disable (in the case of IAA) wq0 and the
device itself before they can set their own attributes and re-enable,
since they've been already been auto-enabled. Note also that in order
for the new configuration to be applied to the deflate-iaa crypto
algorithm the iaa_crypto module needs to unregister the old version,
which is accomplished by removing the iaa_crypto module, and
re-registering it with the new configuration by reinserting the
iaa_crypto module.
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Create a lightweight callback interface to allow idxd sub-drivers to
be notified when work sent to idxd wqs has completed.
For a sub-driver to be notified of work completion, it needs to:
- Set the descriptor's 'Request Completion Interrupt'
(IDXD_OP_FLAG_RCI)
- Set the sub-driver desc_complete() callback when registering the
sub-driver e.g.:
struct idxd_device_driver my_drv = {
.probe = my_probe,
.desc_complete = my_complete,
}
- Set the sub-driver-specific context in the sub-driver's descriptor
e.g:
idxd_desc->crypto.req = req;
idxd_desc->crypto.tfm = tfm;
idxd_desc->crypto.src_addr = src_addr;
idxd_desc->crypto.dst_addr = dst_addr;
When the work completes and the completion irq fires, idxd will invoke
the desc_complete() callback with pointers to the descriptor, context,
and completion_type.
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Acked-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Add the accessors idxd_wq_set_private() and idxd_wq_get_private()
allowing users to set and retrieve a private void * associated with an
idxd_wq.
The private data is stored in the idxd_dev.conf_dev associated with
each idxd_wq.
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Acked-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Rename drv_enable_wq and drv_disable_wq to idxd_drv_enable_wq and
idxd_drv_disable_wq respectively, so that they're no longer too
generic to be exported. This also matches existing naming within the
idxd driver.
And to allow idxd sub-drivers to enable and disable wqs, export them.
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Acked-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Pull dmaengine updates from Vinod Koul:
"New controller support and updates to drivers.
New support:
- Qualcomm SM6115 and QCM2290 dmaengine support
- at_xdma support for microchip,sam9x7 controller
Updates:
- idxd updates for wq simplification and ats knob updates
- fsl edma updates for v3 support
- Xilinx AXI4-Stream control support
- Yaml conversion for bcm dma binding"
* tag 'dmaengine-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine: (53 commits)
dmaengine: fsl-edma: integrate v3 support
dt-bindings: fsl-dma: fsl-edma: add edma3 compatible string
dmaengine: fsl-edma: move tcd into struct fsl_dma_chan
dmaengine: fsl-edma: refactor chan_name setup and safety
dmaengine: fsl-edma: move clearing of register interrupt into setup_irq function
dmaengine: fsl-edma: refactor using devm_clk_get_enabled
dmaengine: fsl-edma: simply ATTR_DSIZE and ATTR_SSIZE by using ffs()
dmaengine: fsl-edma: move common IRQ handler to common.c
dmaengine: fsl-edma: Remove enum edma_version
dmaengine: fsl-edma: transition from bool fields to bitmask flags in drvdata
dmaengine: fsl-edma: clean up EXPORT_SYMBOL_GPL in fsl-edma-common.c
dmaengine: fsl-edma: fix build error when arch is s390
dmaengine: idxd: Fix issues with PRS disable sysfs knob
dmaengine: idxd: Allow ATS disable update only for configurable devices
dmaengine: xilinx_dma: Program interrupt delay timeout
dmaengine: xilinx_dma: Use tasklet_hi_schedule for timing critical usecase
dmaengine: xilinx_dma: Freeup active list based on descriptor completion bit
dmaengine: xilinx_dma: Increase AXI DMA transaction segment count
dmaengine: xilinx_dma: Pass AXI4-Stream control words to dma client
dt-bindings: dmaengine: xilinx_dma: Add xlnx,irq-delay property
...
Pull dmaengine updates from Vinod Koul:
"New support:
- Apple admac t8112 device support
- StarFive JH7110 DMA controller
Updates:
- Big pile of idxd updates to support IAA 2.0 device capabilities,
DSA 2.0 Event Log and completion record faulting features and
new DSA operations
- at_xdmac supend & resume updates and driver code cleanup
- k3-udma supend & resume support
- k3-psil thread support for J784s4"
* tag 'dmaengine-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine: (57 commits)
dmaengine: idxd: add per wq PRS disable
dmaengine: idxd: add pid to exported sysfs attribute for opened file
dmaengine: idxd: expose fault counters to sysfs
dmaengine: idxd: add a device to represent the file opened
dmaengine: idxd: add per file user counters for completion record faults
dmaengine: idxd: process batch descriptor completion record faults
dmaengine: idxd: add descs_completed field for completion record
dmaengine: idxd: process user page faults for completion record
dmaengine: idxd: add idxd_copy_cr() to copy user completion record during page fault handling
dmaengine: idxd: create kmem cache for event log fault items
dmaengine: idxd: add per DSA wq workqueue for processing cr faults
dmanegine: idxd: add debugfs for event log dump
dmaengine: idxd: add interrupt handling for event log
dmaengine: idxd: setup event log configuration
dmaengine: idxd: add event log size sysfs attribute
dmaengine: idxd: make misc interrupt one shot
dt-bindings: dma: snps,dw-axi-dmac: constrain the items of resets for JH7110 dma
dt-bindings: dma: Drop unneeded quotes
dmaengine: at_xdmac: align declaration of ret with the rest of variables
dmaengine: at_xdmac: add a warning message regarding for unpaused channels
...
Add event log processing for faulting of user batch descriptor completion
record.
When encountering an event log entry for a page fault on a completion
record, the driver is expected to do the following:
1. If the "first error in batch" bit in event log entry error info is
set, discard any previously recorded errors associated with the
"batch identifier".
2. Fix the page fault according to the fault address in the event log. If
successful, write the completion record to the fault address in user space.
3. If an error is encountered while writing the completion record and it is
associated to a descriptor in the batch, the driver associates the error
with the batch identifier of the event log entry and tracks it until the
event log entry for the corresponding batch desc is encountered.
While processing an event log entry for a batch descriptor with error
indicating that one or more descs in the batch had event log entries,
the driver will do the following before writing the batch completion
record:
1. If the status field of the completion record is 0x1, the driver will
change it to error code 0x5 (one or more operations in batch completed
with status not successful) and changes the result field to 1.
2. If the status is error code 0x6 (page fault on batch descriptor list
address), change the result field to 1.
3. If status is any other value, the completion record is not changed.
4. Clear the recorded error in preparation for next batch with same batch
identifier.
The result field is for user software to determine whether to set the
"Batch Error" flag bit in the descriptor for continuation of partial
batch descriptor completion. See DSA spec 2.0 for additional information.
If no error has been recorded for the batch, the batch completion record is
written to user space as is.
Tested-by: Tony Zhu <tony.zhu@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Co-developed-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: https://lore.kernel.org/r/20230407203143.2189681-12-fenghua.yu@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
DSA supports page fault handling through PRS. However, the DMA engine
that's processing the descriptor is blocked until the PRS response is
received. Other workqueues sharing the engine are also blocked.
Page fault handing by the driver with PRS disabled can be used to
mitigate the stalling.
With PRS disabled while ATS remain enabled, DSA handles page faults on
a completion record by reporting an event in the event log. In this
instance, the descriptor is completed and the event log contains the
completion record address and the contents of the completion record. Add
support to the event log handling code to fault in the completion record
and copy the content of the completion record to user memory.
A bitmap is introduced to keep track of discarded event log entries. When
the user process initiates ->release() of the char device, it no longer is
interested in any remaining event log entries tied to the relevant wq and
PASID. The driver will mark the event log entry index in the bitmap. Upon
encountering the entries during processing, the event log handler will just
clear the bitmap bit and skip the entry rather than attempt to process the
event log entry.
Tested-by: Tony Zhu <tony.zhu@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Co-developed-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: https://lore.kernel.org/r/20230407203143.2189681-10-fenghua.yu@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Define idxd_copy_cr() to copy completion record to fault address in
user address that is found by work queue (wq) and PASID.
It will be used to write the user's completion record that the hardware
device is not able to write due to user completion record page fault.
An xarray is added to associate the PASID and mm with the
struct idxd_user_context so mm can be found by PASID and wq.
It is called when handling the completion record fault in a kernel thread
context. Switch to the mm using kthread_use_vm() and copy the
completion record to the mm via copy_to_user(). Once the copy is
completed, switch back to the current mm using kthread_unuse_mm().
Suggested-by: Christoph Hellwig <hch@infradead.org>
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Suggested-by: Tony Luck <tony.luck@intel.com>
Tested-by: Tony Zhu <tony.zhu@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20230407203143.2189681-9-fenghua.yu@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Add setup of event log feature for supported device. Event log addresses
error reporting that was lacking in gen 1 DSA devices where a second error
event does not get reported when a first event is pending software
handling. The event log allows a circular buffer that the device can push
error events to. It is up to the user to create a large enough event log
ring in order to capture the expected events. The evl size can be set in
the device sysfs attribute. By default 64 entries are supported as minimal
when event log is enabled.
Tested-by: Tony Zhu <tony.zhu@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Co-developed-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: https://lore.kernel.org/r/20230407203143.2189681-4-fenghua.yu@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Add support for changing of the event log size. Event log is a
feature added to DSA 2.0 hardware to improve error reporting.
It supersedes the SWERROR register on DSA 1.0 hardware and hope
to prevent loss of reported errors.
The error log size determines how many error entries supported for
the device. It can be configured by the user via sysfs attribute.
Tested-by: Tony Zhu <tony.zhu@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Co-developed-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: https://lore.kernel.org/r/20230407203143.2189681-3-fenghua.yu@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
>From Intel IAA spec [1], Intel IAA does not support batch processing.
Two batch related default values for IAA are incorrect in current code:
(1) The max batch size of device is set during device initialization,
that indicates batch is supported. It should be always 0 on IAA.
(2) The max batch size of work queue is set to WQ_DEFAULT_MAX_BATCH (32)
as the default value regardless of Intel DSA or IAA device during
work queue setup and cleanup. It should be always 0 on IAA.
Fix the issues by setting the max batch size of device and max batch
size of work queue to 0 on IAA device, that means batch is not
supported.
[1]: https://cdrdv2.intel.com/v1/dl/getContent/721858
Fixes: 23084545db ("dmaengine: idxd: set max_xfer and max_batch for RO device")
Fixes: 92452a72eb ("dmaengine: idxd: set defaults for wq configs")
Fixes: bfe1d56091 ("dmaengine: idxd: Init and probe for Intel data accelerators")
Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Link: https://lore.kernel.org/r/20220930201528.18621-2-xiaochen.shen@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
DSA 2.0 add the capability of configuring DMA ops on a per workqueue basis.
This means that certain ops can be disabled by the system administrator for
certain wq. By default, all ops are available. A bitmap is used to store
the ops due to total op size of 256 bits and it is more convenient to use a
range list to specify which bits are enabled.
One of the usage to support this is for VM migration between different
iteration of devices. The newer ops are disabled in order to allow guest to
migrate to a host that only support older ops. Another usage is to
restrict the WQ to certain operations for QoS of performance.
A sysfs of ops_config attribute is added per wq. It is only usable when the
ops_config bit is set under WQ_CAP register. This means that this attribute
will return -EOPNOTSUPP on DSA 1.x devices. The expected input is a range
list for the bits per operation the WQ supports.
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Co-developed-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: https://lore.kernel.org/r/20220917161222.2835172-4-fenghua.yu@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
To make input and output consistent and prepping for the per WQ operation
configuration support, change the output of opcap display to match the
input that is expected by bitmap_parse() helper function. The output will
be a bitmap with field width as the number of bits using the %*pb format
specifier for printk() family.
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Co-developed-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: https://lore.kernel.org/r/20220917161222.2835172-3-fenghua.yu@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
