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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <743pqjv2sefs3bhsyyoezv2nzf6tcbc6fo5nshczsc3s36j3qy@2xla3yxhbhpd>
Date: Tue, 25 Nov 2025 15:54:08 -0600
From: Lucas De Marchi <lucas.demarchi@...el.com>
To: ZhangZhiJie <zhangzhijie@...c.ac.cn>
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 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@intel.com/

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