From mboxrd@z Thu Jan  1 00:00:00 1970
From: schmitz <schmitz@biophys.uni-duesseldorf.de>
Subject: Re: [PATCH 2/2] m68k/atari - atafb: convert allocation of fb ram
 to new interface
Date: Sat, 22 Mar 2014 20:36:11 +1300
Message-ID: <532D3D6B.4040600@biophys.uni-duesseldorf.de>
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To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Michael Schmitz <schmitzmic@gmail.com>, Linux/m68k <linux-m68k@vger.kernel.org>, Debian m68k <debian-68k@lists.debian.org>, Michael Schmitz <schmitz@debian.org>

Hi Geert,
>>> I guess it dies in register_framebuffer() - the next log entry is 
>>> missing:
>>>
>>>        fb_info(&fb_info, "frame buffer device, using %dK of video 
>>> memory\n",
>>>                screen_len >> 10);
>>>     
>>
>> And register_framebuffer() will write to the frame buffer, I think.
>> So info->screen_base may be incorrect.
>>
>> Yep:
>>
>> static void atafb_set_disp(struct fb_info *info)
>> {
>>         atafb_get_var(&info->var, info);
>>         atafb_get_fix(&info->fix, info);
>>
>>         info->screen_base = (void *)info->fix.smem_start;
>> }
>>
>> Missing atari_stram_to_virt().
>>   
>
> Should have had phys_to_virt() before I guess. Thanks.

Bingo!

>
>> Any other casts that indicate bugs? ;-)
>>   
>
> Probably - I'll go over the source again. My port of atafb a few years 
> back was none too subtle.
>

Only a few more - in the external VGA adapter code, in the ioctl code 
(copy tp/from user) and one in the atafb_imageblit() that I'm fairly 
sure is dead code.

ARAnyM is happy - I'll have yet to see how this works on real hardware. 
We might yet need a writethrough mapping for performance.

In the interest of minimizing casts, I'll rewrite the virt/phys 
translation helpers and clean up the rest of the code a bit more. Saves 
a bit of headache when I need to revisit this code in another decade or 
so :-)

Thanks again for your help in tracking this down.

Cheers,

    Michael