Sure.
I will make it a bit later, when I have the more stable result.
Best regards,
Alexander
>Понедельник, 20 апреля 2020, 8:59 +03:00 от Oleksandr Andrushchenko
><oleksandr_andrushche...@epam.com>:
>
>Hi,
>
>On 4/19/20 14:26, Santucco wrote:
>> Hello,
>> I have found a source of the problem.
>> In displ_be, BaseDump copies to the drm buffer with a size from
>> i915 drm driver, but this size a bit more than a size of my frontend
>> display buffer. I have made a quick and dirty fix, a copy a line of my
>> display buffer to a middle of a line of the drm display buffer. Patch
>> is attached.
>
>Thank you for the patch and your efforts to fix the issue.
>
>Could you please make a pull request to [1], so we can continue there?
>
>Thank you in advance,
>
>Oleksandr
>
>> Best regards,
>> Alexander
>>
>> Четверг, 6 февраля 2020, 11:20 +03:00 от Oleksandr Andrushchenko
>> < oleksandr_andrushche...@epam.com >:
>> On 2/5/20 8:59 PM, Santucco wrote:
>> > Hello,
>> > Ok, I commented out the memcpy call and run the test.
>> > displ_be hasn’t crached, I have seen FLIP events in the log.
>> > But there hasn’t been the black screen, just a blink effect every
>> > couple of seconds.
>> > Logs are attached.
>> Ok, so I believe that frontend - backend (displ_be) communication
>> is ok
>> and there is nothing to do there.
>>
>> Next, I would start debugging the following in Xen:
>> (XEN) mm.c:2223:d2v0 Bad L1 flags 80
>> and have a look at [1]. Probably, someone on Xen x86 side can tell
>> if this could be related to the flags at [2].
>>
>> > Best regards,
>> > Alexander
>> >
>> > Среда, 5 февраля 2020, 9:31 +03:00 от Oleksandr Andrushchenko
>> > < oleksandr_andrushche...@epam.com
>> </compose?To=oleksandr_andrushche...@epam.com>>:
>> > On 2/4/20 10:28 AM, Santucco wrote:
>> > > Hello,
>> > > displ_be was compiled without zero-copy support early.
>> > > I have tried with the recompiled dom0 kernel, a result is the
>> same.
>> > > Logs and configs (+displ_be’s CMakeCache.txt ) are attached.
>> > Ok, yet another test to localize the problem.
>> > Could you please remove memcpy from
>> > #1 0x000055e5a1f28bec in Drm::DumbDrm::copy
>> (this=0x7f9338000e00) at
>> >
>> /home/santucco/tmp/xen-troops/displ_be/src/displayBackend/drm/Dumb.cpp:149
>> > and just memset the destination with 0 or whatever.
>> >
>> > I expect that system won't crash, nothing will be shown (black
>> > screen), but
>> > displ_be will show page flip events in its logs.
>> > > Best regards,
>> > > Alexander
>> > >
>> > > Понедельник, 3 февраля 2020, 10:36 +03:00 от Oleksandr
>> > > Andrushchenko < oleksandr_andrushche...@epam.com
>> </compose?To=oleksandr_andrushche...@epam.com>
>> > </compose?To=oleksandr_andrushche...@epam.com>>:
>> > >
>> > >
>> > > On 2/1/20 4:39 PM, Santucco wrote:
>> > > > Hello again,
>> > > > I have not yet made to work my drm client, so I have tried
>> to run
>> > > > linux like a domU (to see how it should work), it doesn’t
>> work too
>> > > > — displ_be catches SIGSEGV:
>> > > >
>> > > > #0 0x00007f4afed1c161 in ?? () from /lib64/libc.so.6
>> > > > #1 0x000055723b9c5bec in Drm::DumbDrm::copy
>> > > (this=0x7f4adc000e00) at
>> > > >
>> > >
>> >
>> /home/santucco/tmp/xen-troops/displ_be/src/displayBackend/drm/Dumb.cpp:149
>> > > > #2 0x000055723b9a8f51 in BuffersStorage::getFrameBufferAndCopy
>> > > > (this=0x7f4ae00010e0, fbCookie=18446612682295083264) at
>> > > >
>> > >
>> >
>> /home/santucco/tmp/xen-troops/displ_be/src/displayBackend/BuffersStorage.cpp:165
>> > > > It tries to copy to mBuffer with non-accessible address.
>> > > > For the moment I see a strange offset for mmap call of
>> > > /dev/drm/card0
>> > > > in the strace log — 0x100000000. Is that normal?
>> > > > Any direction of which to dig will be very helpful.
>> > > > Configuration details:
>> > > > Xen 4.12.1 Dom0: Linux 4.20.17-gentoo #13 SMP Sat Dec 28
>> > > 11:12:24 MSK
>> > > > 2019 x86_64 Intel(R) Celeron(R) CPU N3050 @ 1.60GHz GenuineIntel
>> > > GNU/Linux
>> > > > DomU: Linux 4.20.17-gentoo
>> > > > last xen-troops/libxenbe and xen-troops/displ_be
>> > > > Logs (dmesg, xl dmesg, displ_be, strace log of displ_be), a
>> > > backtrace
>> > > > of gdb and kernel configs are attached.
>> > > > Thanks in advance.
>> > > Could you please try Dom0 kernel WITHOUT the options below:
>> > > CONFIG_XEN_GNTDEV_DMABUF=y
>> > > CONFIG_XEN_GRANT_DMA_ALLOC=y
>> > >
>> > > Then, just to make sure, did you build displ_be without zero-copy
>> > > support?
>> > >
>> > > > On 1/8/20 5:38 PM, Santucco wrote:
>> > > > > Thank you very much for all your answers.
>> > > > >
>> > > > > Среда, 8 января 2020, 10:54 +03:00 от Oleksandr Andrushchenko
>> > > > > < oleksandr_andrushche...@epam.com
>> </compose?To=oleksandr_andrushche...@epam.com>
>> > </compose?To=oleksandr_andrushche...@epam.com>
>> > > > > </compose?To=oleksandr_andrushche...@epam.com>>:
>> > > > > On 1/6/20 10:38 AM, Jürgen Groß wrote:
>> > > > > > On 06.01.20 08:56, Santucco wrote:
>> > > > > >> Hello,
>> > > > > >>
>> > > > > >> I’m trying to use vdispl interface from PV OS, it doesn’t
>> > work.
>> > > > > >> Configuration details:
>> > > > > >> Xen 4.12.1
>> > > > > >> Dom0: Linux 4.20.17-gentoo #13 SMP Sat Dec 28
>> > 11:12:24 MSK
>> > > > > 2019
>> > > > > >> x86_64 Intel(R) Celeron(R) CPU N3050 @ 1.60GHz GenuineIntel
>> > > > > GNU/Linux
>> > > > > >> DomU: x86 Plan9, PV
>> > > > > >> displ_be as a backend for vdispl and vkb
>> > > > > >>
>> > > > > >> when VM starts, displ_be reports about an error:
>> > > > > >> gnttab: error: ioctl DMABUF_EXP_FROM_REFS failed: Invalid
>> > > argument
>> > > > > >> (displ_be.log:221)
>> > > > > >>
>> > > > > >> related Dom0 output is:
>> > > > > >> [ 191.579278] Cannot provide dma-buf: use_ptemode 1
>> > > > > >> (dmesg.create.log:123)
>> > > > > >
>> > > > > > This seems to be a limitation of the xen dma-buf driver.
>> > It was
>> > > > > written
>> > > > > > for being used on ARM initially where PV is not available.
>> > > > > This is true and we never tried/targeted PV domains with this
>> > > > > implementation,
>> > > > > so if there is a need for that someone has to take a look
>> on the
>> > > > > proper
>> > > > > implementation for PV…
>> > > > >
>> > > > > Have I got your right and there is no the proper
>> > > implementation :-)?
>> > > > There is no
>> > > > >
>> > > > > >
>> > > > > > CC-ing Oleksandr Andrushchenko who is the author of that
>> > > driver. He
>> > > > > > should be able to tell us what would be needed to enable PV
>> > > dom0.
>> > > > > >
>> > > > > > Depending on your use case it might be possible to use PVH
>> > > dom0, but
>> > > > > > support for this mode is "experimental" only and some
>> features
>> > > > > are not
>> > > > > > yet working.
>> > > > > >
>> > > > > Well, one of the workarounds possible is to drop zero-copying
>> > > use-case
>> > > > > (this is why display backend tries to create dmu-bufs from
>> > grants
>> > > > > passed
>> > > > > by the guest domain and fails because of "Cannot provide
>> > dma-buf:
>> > > > > use_ptemode 1")
>> > > > > So, in this case display backend will do memory copying
>> for the
>> > > > > incoming
>> > > > > frames
>> > > > > and won't touch DMABUF_EXP_FROM_REFS ioctl.
>> > > > > To do so just disable zero-copying while building the
>> > backend [1]
>> > > > >
>> > > > > Thanks, I have just tried the workaround. The backend
>> has failed
>> > > > > in an other place not corresponding with dma_buf.
>> > > > > Anyway it is enough to continue debugging my
>> > > frontend implementation.
>> > > > > Do you know how big is performance penalty in comparison with
>> > > > > the zero-copy variant?
>> > > > Well, it solely depends on your setup, so I cannot tell what
>> > > > would the numbers be in your case. Comparing to what I have
>> > doesn't
>> > > > make any sense to me: one should compare apples to apples
>> > > > > Does it make a sense if I make a dedicated HVM domain with
>> > > linux only
>> > > > > for the purpose of vdispl and vkbd backends? Is there a
>> > hope this
>> > > > > approach will work?
>> > > > You can try if this approach fits your design and requirements
>> > > > >
>> > > > > >
>> > > > > > Juergen
>> > > > > >
>> > > > > [1]
>> > > > >
>> > > >
>> > >
>> >
>> https://github.com/xen-troops/displ_be/blob/master/CMakeLists.txt#L12
>> <
>> https://urldefense.com/v3/__https://github.com/xen-troops/displ_be/blob/master/CMakeLists.txt*L12__;Iw!!GF_29dbcQIUBPA!mhlQAPS_Ozy57xa_0OR66qc1mjlSEz7lj3MkWCyDDF91BGa7J7-BOYWYcdksplocZvxIZMirWg$
>> >
>> >
>> <
>> https://urldefense.com/v3/__https://github.com/xen-troops/displ_be/blob/master/CMakeLists.txt*L12__;Iw!!GF_29dbcQIUBPA!kZ1JQFRS2pXj_IuXBhvYhmP9Q_svcLyjCXK9465ULGB4MeiYPRz2cF7lepHggr9UxPU9zOBEUw$
>> >
>> > >
>> >
>> <
>> https://urldefense.com/v3/__https://github.com/xen-troops/displ_be/blob/master/CMakeLists.txt*L12__;Iw!!GF_29dbcQIUBPA!kvDgy3X0IuSQk7D2DdsGtsjtyGroYbNKOrPG95OpyoAkuBVbFSmzozwfor05jkRl0ita0FumBw$
>> >
>> > > >
>> > >
>> >
>> <
>> https://urldefense.com/v3/__https://github.com/xen-troops/displ_be/blob/master/CMakeLists.txt*L12__;Iw!!GF_29dbcQIUBPA!gi81oZZNvWaFWUVnaZluA_mNBAItLMd4RZmnc-M_FmlpDojqeQQnS7aXSNlbo80re9uOl2wqFA$
>> >
>> > > > >
>> > > >
>> > >
>> >
>> <
>> https://urldefense.com/v3/__https://github.com/xen-troops/displ_be/blob/master/CMakeLists.txt*L12__;Iw!!GF_29dbcQIUBPA!mz3gn1wQMX2DXeNuAV-1_dI7nxFYYZOgdPiJNSFMesCz9lAzOKlwVPlddbxbcLmUO44NOy0TFA$
>> >
>> > > > >
>> > > > > Best regards,
>> > > > > Alexander Sychev
>> > > >
>> > >
>> > >
>> >
>> ------------------------------------------------------------------------
>> >
>> [1]
>> https://elixir.bootlin.com/linux/v5.5/source/drivers/xen/gntdev.c#L300
>> <
>> https://urldefense.com/v3/__https://elixir.bootlin.com/linux/v5.5/source/drivers/xen/gntdev.c*L300__;Iw!!GF_29dbcQIUBPA!mhlQAPS_Ozy57xa_0OR66qc1mjlSEz7lj3MkWCyDDF91BGa7J7-BOYWYcdksplocZvzn6flk6Q$
>> >
>> [2]
>> https://elixir.bootlin.com/linux/v5.5/source/drivers/xen/gntdev.c#L319
>> <
>> https://urldefense.com/v3/__https://elixir.bootlin.com/linux/v5.5/source/drivers/xen/gntdev.c*L319__;Iw!!GF_29dbcQIUBPA!mhlQAPS_Ozy57xa_0OR66qc1mjlSEz7lj3MkWCyDDF91BGa7J7-BOYWYcdksplocZvwjOfYJxg$
>> >
>>
>
>[1] https://github.com/xen-troops/displ_be
