Re: [PATCH 02/24] display/xlnx_dp: Fix to realize "i2c-ddc" and "aux-to-i2c-bridge"

[Markus Armbruster]

Philippe Mathieu-Daudé <address@hidden> writes:

> On 5/18/20 12:30 PM, Peter Maydell wrote:
>> On Mon, 18 May 2020 at 06:04, Markus Armbruster <address@hidden> wrote:
>>>
>>> xlnx_dp_init() creates these two devices, but they're never realized.
>>> Affects machine xlnx-zcu102.
>>>
>>> I wonder how this ever worked.  If the "device becomes real only on
>>> realize" thing actually works, then we've always been missing these
>>> two devices, yet nobody noticed.
>>
>> It depends entirely on the implementation of the device.
>> If it happens to do nothing in the realize method that
>> matters

Also in the realize methods of supertypes.

>>         (eg i2c-ddc has no realize method and does the limited
>> amount of initialization it needs in instance_init) then the
>> device will (by lucky accident) work just fine.

Yes.

>> We should really ideally have an assert() in the DeviceClass
>> reset that the device was realized, so we can keep this kind
>> of bug out of the codebase. (Last time I looked it wasn't obvious
>> exactly where to put the assert now that we have both legacy-reset
>> and three-phase-reset, unfortunately.)
>
> Your wish came true in the last patch of this series! #24:
> https://www.mail-archive.com/address@hidden/msg704239.html

Not exactly what Peter asked for, but hopefully close enough for
practical purposes.