linux-kernel - Re: [PATCH v6] staging: fbtft: Use fbdev logging helpers when FB

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Message-ID: <ed199efe-f6b2-426e-b679-ef1f019e6433@gmail.com>
Date: Wed, 14 Jan 2026 20:05:01 -0800
From: Chintan Patel <chintanlike@...il.com>
To: Thomas Zimmermann <tzimmermann@...e.de>,
 Greg KH <gregkh@...uxfoundation.org>
Cc: linux-fbdev@...r.kernel.org, linux-staging@...ts.linux.dev,
 linux-omap@...r.kernel.org, linux-kernel@...r.kernel.org,
 dri-devel@...ts.freedesktop.org, andy@...nel.org, deller@....de,
 kernel test robot <lkp@...el.com>
Subject: Re: [PATCH v6] staging: fbtft: Use fbdev logging helpers when
 FB_DEVICE is disabled



On 1/14/26 03:38, Thomas Zimmermann wrote:
> Hi
> 
> Am 13.01.26 um 07:16 schrieb Greg KH:
>> On Mon, Jan 12, 2026 at 08:59:09PM -0800, Chintan Patel wrote:
>>> Replace direct accesses to info->dev with fb_dbg() and fb_info()
>>> helpers to avoid build failures when CONFIG_FB_DEVICE=n.
>> Why is there a fb_* specific logging helper?  dev_info() and dev_dbg()
>> should be used instead.
> 
> Fbdev is entirely inconsistent about its logging. There's dev_*(), 
> there's pr_*(), and even printk(). The problem with dev_*() logging is 
> that devices are not always available. The HW device can be NULL and 
> might not be all that useful in practice. The Fbdev software device is 
> often not even compiled in nowadays. (This patch is about that problem.) 
> Hence the next best option is to make fb_*() logging helpers that 
> address these problems. They are based on pr_*() and print the 
> framebuffer index, which should always be available after 
> register_framebuffer().
> 
>>

Thanks Andy and Thomas.

I’ll update the commit message to clearly describe the underlying issue.

I’ll also split the changes as suggested in 2 patches and send v7:
1) a patch focused purely on fixing the compilation issue by avoiding
    info->dev dereferences (using fb_dbg() where logging remains), and
2) a follow-up cleanup that removes or downgrades the framebuffer
    registration message to debug level.

I’ll rework the series accordingly and resend.

Thanks for the guidance.