linux-kernel - Re: [PATCH v2] i915: Support Intel GPU porting on any non-x86 system.

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Message-ID: <0d2e6a53-11f8-403c-a4e8-b9c367ed96a8@bosc.ac.cn>
Date: Wed, 26 Nov 2025 09:39:37 +0800
From: ZhangZhiJie <zhangzhijie@...c.ac.cn>
To: Lucas De Marchi <lucas.demarchi@...el.com>
Cc: Jani Nikula <jani.nikula@...ux.intel.com>, jeff@...fgeerling.com,
 wangran@...c.ac.cn, zhangjian@...c.ac.cn, daniel@...ll.ch,
 rodrigo.vivi@...el.com, joonas.lahtinen@...ux.intel.com,
 tursulin@...ulin.net, airlied@...il.com, intel-gfx@...ts.freedesktop.org,
 intel-xe@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
 linux-kernel@...r.kernel.org, guoyaxing@...c.ac.cn
Subject: Re: [PATCH v2] i915: Support Intel GPU porting on any non-x86 system.



On 2025/11/26 05:54, Lucas De Marchi wrote:
> On Tue, Nov 25, 2025 at 06:20:00PM +0800, ZhangZhiJie wrote:
>>
>>
>> On 2025/11/25 18:13, Jani Nikula wrote:
>>> On Tue, 25 Nov 2025, ZhangZhiJie <zhangzhijie@...c.ac.cn> wrote:
>>>> On 2025/11/24 20:24, Jani Nikula wrote:
>>>>> On Mon, 24 Nov 2025, zhangzhijie <zhangzhijie@...c.ac.cn> wrote:
>>>>>> inb/outb speccial wire not support on other ARCH.
>>>>>> Should detect whether arch platform support or not.
>>>>>
>>>>> Seems to me it inb/outb depend on CONFIG_HAS_IOPORT. Which arch are 
>>>>> you
>>>>> talking about specifically?
>>>>
>>>> riscv , has CONFIG_HAS_IOPORT.  is using for serial, GPIO., etc.
>>>
>>> What is the actual failure mode you see?
>>>
>>> Does it build?
>>>
>>> BR,
>>> Jani.
>>>
>> Yes, i compiled Xe driver, and it's occured load access fault when not 
>> disable  VGA_SEQ_*.
>>
>> can found this link https://github.com/geerlingguy/raspberry-pi-pcie- 
>> devices/issues/510#issuecomment-3383284831
> 
> and this is what I tested with rpi:
> https://lore.kernel.org/intel-xe/20251119-ioport-v1-1- 
> ec43f1e12c49@...el.com/
> 
Yep. agree like this patch.

In my mind. if machine not implement VGA_SEQ_* ioport.
should avoid access ioports about VGA_SEQ_* .

Can you give  log for bootting on non-x86 arch?

> not sure why you are changing the intel_vga_disable() function: out of
> reset that bit is disabled and the function does nothing:
> 
>      tmp = intel_de_read(display, vga_reg);
>      if (tmp & VGA_DISP_DISABLE)
>          return;
> 
> If there's no VGA, no bios, then there isn't anything enabling that and
> we don't need to disable it.
> 
> I have a patch that moves the vga access to a separate function,
> intel_vga_set_screen_off(), but that's mostly for clarity, not to fix
> anything. If later we want to add an ifdef then we'd probably have to
> implement the alternative.
> 
> Also note that not having CONFIG_HAS_IOPORT doesn't mean inb()/outb()
> are not implemented. See arch/{arm,powerpc,sparc}/include/asm/io.h
> for a few variants.
> 
> Lucas De Marchi

BR.
ZhiJie