Re: [PATCH v3 3/4] fbmem: Check screen resolution change against font size

[Helge Deller <deller@gmx.de>]

On 6/26/22 00:33, Daniel Vetter wrote:
> On Sun, Jun 26, 2022 at 12:06:29AM +0200, Helge Deller wrote:
>> Enhance the check in the FBIOPUT_VSCREENINFO ioctl handler to verify if the
>> user-provided new screen size is bigger than the current font size.
>>
>> Signed-off-by: Helge Deller <deller@gmx.de>
>> Cc: stable@vger.kernel.org # v5.4+
>
> Please squash with previous patch.

Will do.

> You might also want to add a note there
> that on older kernels backporters need to open-code
> fbcon_info_from_console instead, since it only exists since
> 409d6c95f9c6 ("fbcon: Introduce wrapper for console->fb_info lookup")

Good catch!
For sake of easier backportability I will change this (joined with previous) patch
to use registered_fb[]. Those patches can then easily be pushed backwards.
In addition I'll add another patch to this series which fixes registered_fb[] usage
back to fbcon_info_from_console(). That patch is only applied to v5.19.

Will send new series...

Helge

>
> With these two nits: Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
>
>> ---
>>  drivers/video/fbdev/core/fbmem.c | 4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
>> index afa2863670f3..160389365a36 100644
>> --- a/drivers/video/fbdev/core/fbmem.c
>> +++ b/drivers/video/fbdev/core/fbmem.c
>> @@ -1106,7 +1106,9 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
>>  			return -EFAULT;
>>  		console_lock();
>>  		lock_fb_info(info);
>> -		ret = fb_set_var(info, &var);
>> +		ret = fbcon_modechange_possible(info, &var);
>> +		if (!ret)
>> +			ret = fb_set_var(info, &var);
>>  		if (!ret)
>>  			fbcon_update_vcs(info, var.activate & FB_ACTIVATE_ALL);
>>  		unlock_fb_info(info);
>> --
>> 2.35.3
>>
>