[SRU] [B/C/D] [PATCH 0/8] Sync AMD MP2 I2C driver with upstream version

[Stefan Bader]

On 24.04.19 11:05, Kai-Heng Feng wrote:
> at 14:23, Khaled Elmously <khalid.elmously at canonical.com> wrote:
> 
>> On 2019-04-17 22:55:42 , Kai-Heng Feng wrote:
>>> at 22:33, Stefan Bader <stefan.bader at canonical.com> wrote:
>>>
>>>> On 02.04.19 05:38, Kai-Heng Feng wrote:
>>>>> BugLink: https://bugs.launchpad.net/bugs/1787775
>>>>>
>>>>> [Impact]
>>>>> AMD MP2 I2C driver doesn't support more than one bus.
>>>>> This makes touchpad on Lenovo Yoga 530 doensn't work as expected.
>>>>>
>>>>> [Fix]
>>>>> Sync the MP2 driver with upstream version.
>>>>>
>>>>> [Test]
>>>>> The new upstream driver doesn't break on Latitude 5495.
>>>>> Users haven't given any feedback yet, but since Disco is freezing I
>>>>> am sending this out.
>>>>>
>>>>> [Regression Potential]
>>>>> Low. It's from upstream, and only a subset of Raven Ridge has this
>>>>> device.
>>>>>
>>>>> Elie Morisse (1):
>>>>>   i2c: Add drivers for the AMD PCIe MP2 I2C controller
>>>>>
>>>>> Kai-Heng Feng (4):
>>>>>   Revert "UBUNTU: SAUCE: i2c:amd Depends on ACPI"
>>>>>   Revert "UBUNTU: SAUCE: i2c:amd move out pointer in union
>>>>>     i2c_event_base"
>>>>>   Revert "UBUNTU: SAUCE: i2c:amd I2C Driver based on PCI Interface for
>>>>>     upcoming platform"
>>>>>   UBUNTU: [Config] Update config for AMD MP2 I2C driver
>>>>>
>>>>> Wolfram Sang (3):
>>>>>   i2c: add helpers to ease DMA handling
>>>>>   i2c: add a message flag for DMA safe buffers
>>>>>   i2c: add extra check to safe DMA buffer helper
>>>>>
>>>>>  Documentation/i2c/busses/i2c-amd-mp2          |  23 +
>>>>>  MAINTAINERS                                   |   8 +
>>>>>  .../config/amd64/config.common.amd64          |   2 +-
>>>>>  debian.master/config/i386/config.common.i386  |   2 +-
>>>>>  drivers/i2c/busses/Kconfig                    |  12 +-
>>>>>  drivers/i2c/busses/Makefile                   |   3 +-
>>>>>  drivers/i2c/busses/i2c-amd-mp2-pci.c          | 483 ++++++++++++++
>>>>>  drivers/i2c/busses/i2c-amd-mp2-plat.c         | 367 ++++++++++
>>>>>  drivers/i2c/busses/i2c-amd-mp2.h              | 219 ++++++
>>>>>  drivers/i2c/busses/i2c-amd-pci-mp2.c          | 625 ------------------
>>>>>  drivers/i2c/busses/i2c-amd-pci-mp2.h          | 253 -------
>>>>>  drivers/i2c/busses/i2c-amd-platdrv.c          | 335 ----------
>>>>>  drivers/i2c/i2c-core-base.c                   |  51 ++
>>>>>  include/linux/i2c.h                           |   3 +
>>>>>  include/uapi/linux/i2c.h                      |   3 +
>>>>>  15 files changed, 1166 insertions(+), 1223 deletions(-)
>>>>>  create mode 100644 Documentation/i2c/busses/i2c-amd-mp2
>>>>>  create mode 100644 drivers/i2c/busses/i2c-amd-mp2-pci.c
>>>>>  create mode 100644 drivers/i2c/busses/i2c-amd-mp2-plat.c
>>>>>  create mode 100644 drivers/i2c/busses/i2c-amd-mp2.h
>>>>>  delete mode 100644 drivers/i2c/busses/i2c-amd-pci-mp2.c
>>>>>  delete mode 100644 drivers/i2c/busses/i2c-amd-pci-mp2.h
>>>>>  delete mode 100644 drivers/i2c/busses/i2c-amd-platdrv.c
>>>> I am a bit hesitant to do this especially in Bionic. Have you done any
>>>> wider
>>>> regression testing with other hardware which uses this driver? That one
>>>> Dell
>>>> might be better off but that would not necessarily guarantee that
>>>> nothing else
>>>> does regress.
>>>
>>> No we’ve only enabled one system with AMD MP2. So it’s the only system I can
>>> test.
>>>
>>> So there’s no guarantee. What I can confirm is that it used to only work on
>>> the Dell system, now it works on both the Dell one and Lenovo Yoga.
>>>
>>>> Also the config changes silently change things from being built-in for
>>>> 32bit and
>>>> 64bit kernels to only being available as a module for 64bit kernels.
>>>> That would
>>>> mean any user who was running 32bit will loose that driver support. And
>>>> you can
>>>> be sure that if there is any possibility of doing that, there will be
>>>> some user
>>>> who did.
>>>
>>> Ryzen based systems only support 64bits [1]:
>>> *OS Support
>>> Windows 10 - 64-Bit Edition
>>> RHEL x86 64-Bit
>>> Ubuntu x86 64-Bit
>>>
>>> [1] https://www.amd.com/en/products/apu/amd-ryzen-5-2500u
>>
>> I had thought the AMD64 specification explicitly supports i386 as "legacy
>> mode", as per page 2 of [2]
> 
> CPU-wise yes. But the chipset and other components comes with Ryzen
> 
> I just tried to boot a live 16.04.6 image on a Ryzen system, and it hangs at
> certain point.
> 
>>
>> Is there a reason the MP2 driver can no longer be built for 32-bit?
> 
> Of course it can be built agains 32-bit, but Ryzen as a whole doesn’t really
> support 32-bit OS.

This is a problem for a stable update. We have released with the driver built-in
for both amd64 and i386. So we cannot take away that support with any stable
update. Even if in theory nothing can use it.

-Stefan

> 
> Kai-Heng
> 
>>
>>
>> [2] https://www.amd.com/system/files/TechDocs/24592.pdf
>>
>>
>>
>>> Kai-Heng
>>>
>>>> -Stefan
>>>
>>>
>>>
>>> -- 
>>> kernel-team mailing list
>>> kernel-team at lists.ubuntu.com
>>> https://lists.ubuntu.com/mailman/listinfo/kernel-team
> 
> 


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