RE: [PATCH] drm/dumb-buffers: Increase size limits to match current devices

[Jani Nikula <jani.nikula@linux.intel.com>]

On Tue, 02 Jun 2026, "Saarinen, Jani" <jani.saarinen@intel.com> wrote:
> Hi, 
>> -----Original Message-----
>> From: Thomas Zimmermann <tzimmermann@suse.de>
>> Sent: Tuesday, 2 June 2026 10.30
>> To: rajat.gupta@oss.qualcomm.com; jani.nikula@linux.intel.com; Saarinen,
>> Jani <jani.saarinen@intel.com>; simona@ffwll.ch; airlied@gmail.com;
>> mripard@kernel.org; maarten.lankhorst@linux.intel.com
>> Cc: dri-devel@lists.freedesktop.org; intel-gfx@lists.freedesktop.org; intel-
>> xe@lists.freedesktop.org; Thomas Zimmermann <tzimmermann@suse.de>
>> Subject: [PATCH] drm/dumb-buffers: Increase size limits to match current
>> devices
>> 
>> Increase the limits for dumb-buffer arguments to sizes of 16384x16384 at 64
>> bpp. Such buffer sizes are still within 32-bit unsigned limits.
>> Fixes CI and high-end devices.
>> 
>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>> Fixes: 5ab62dd3687b ("drm: prevent integer overflows in dumb buffer
>> creation helpers")
>> Reported-by: Jani Nikula <jani.nikula@linux.intel.com>
>> Closes: https://lore.kernel.org/dri-
>> devel/ddf0233e50044059c85279f928661563ef6a55bf@intel.com/
>
> Seems not helping on i915 CI BAT issue https://lore.kernel.org/intel-gfx/178038951063.34290.3796875109342598028@6beec6c84f66/T/#u 
> => https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_167719v1/index.html?

Right, so vgem_basic has this, among other things:

	bo.width = 1<<15;
	bo.height = 1<<15;
	bo.bpp = 16;
	vgem_create(fd, &bo);

i.e. 32768x32768.

Not so sure about this one.

Anyone else care to chime in?


BR,
Jani.

>
>> Cc: Rajat Gupta <rajat.gupta@oss.qualcomm.com>
>> Cc: Thomas Zimmermann <tzimmermann@suse.de>
>> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
>> Cc: Maxime Ripard <mripard@kernel.org>
>
> Br,
> Jani
>
>> ---
>>  drivers/gpu/drm/drm_dumb_buffers.c | 9 +++++----
>>  1 file changed, 5 insertions(+), 4 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/drm_dumb_buffers.c
>> b/drivers/gpu/drm/drm_dumb_buffers.c
>> index e60130b2bb0c..9c4cfb3210aa 100644
>> --- a/drivers/gpu/drm/drm_dumb_buffers.c
>> +++ b/drivers/gpu/drm/drm_dumb_buffers.c
>> @@ -201,11 +201,12 @@ int drm_mode_create_dumb(struct drm_device
>> *dev,
>>  	if (!args->width || !args->height || !args->bpp)
>>  		return -EINVAL;
>> 
>> -	/* Reject unreasonable inputs early.  Dumb buffers are for software
>> -	 * rendering; nothing legitimate needs more than 8192x8192 at
>> 32bpp.
>> -	 * This prevents overflows in downstream alignment helpers.
>> +	/*
>> +	 * Reject unreasonable inputs early. Dumb buffers are for software
>> +	 * rendering; nothing legitimate needs more than 16384x16384 at
>> +	 * 64 bpp. This prevents overflows in downstream alignment helpers.
>>  	 */
>> -	if (args->width >= 8192 || args->height >= 8192 || args->bpp > 32)
>> +	if (args->width > 16384 || args->height > 16384 || args->bpp > 64)
>>  		return -EINVAL;
>> 
>>  	/* overflow checks for 32bit size calculations */
>> 
>> base-commit: a980196655477a8f5067112946401fe52e510664
>> --
>> 2.54.0
>

-- 
Jani Nikula, Intel