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

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Message-ID: <c7e6fe1c-ff46-4541-ab6c-6dd776924f95@gmail.com>
Date: Thu, 15 Jan 2026 18:59:16 -0800
From: Chintan Patel <chintanlike@...il.com>
To: Thomas Zimmermann <tzimmermann@...e.de>, linux-fbdev@...r.kernel.org,
 linux-staging@...ts.linux.dev, linux-omap@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
 andy@...nel.org, deller@....de, gregkh@...uxfoundation.org,
 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 23:55, Thomas Zimmermann wrote:
> Hi
> 
> Am 13.01.26 um 05:59 schrieb Chintan Patel:
>> Replace direct accesses to info->dev with fb_dbg() and fb_info()
>> helpers to avoid build failures when CONFIG_FB_DEVICE=n.
>>
>> Fixes: a06d03f9f238 ("staging: fbtft: Make FB_DEVICE dependency 
>> optional")
>> Reported-by: kernel test robot <lkp@...el.com>
>> Closes: https://lore.kernel.org/oe-kbuild-all/202601110740.Y9XK5HtN- 
>> lkp@...el.com
>> Signed-off-by: Chintan Patel <chintanlike@...il.com>
>>
>> Changes in v6:
>> - Switch debug/info logging to fb_dbg() and fb_info()(suggested by 
>> Thomas Zimmermann)
>> - Drop dev_of_fbinfo() usage in favor of framebuffer helpers that 
>> implicitly
>>    handle the debug/info context.
>> - Drop __func__ usage per review feedback(suggested by greg k-h)
>> - Add Fixes tag for a06d03f9f238 ("staging: fbtft: Make FB_DEVICE 
>> dependency optional")
>>    (suggested by Andy Shevchenko)
>>
>> Changes in v5:
>> - Initial attempt to replace info->dev accesses using
>>    dev_of_fbinfo() helper
>> ---
>>   drivers/staging/fbtft/fbtft-core.c | 19 +++++++++----------
>>   1 file changed, 9 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/staging/fbtft/fbtft-core.c b/drivers/staging/ 
>> fbtft/fbtft-core.c
>> index 8a5ccc8ae0a1..1b3b62950205 100644
>> --- a/drivers/staging/fbtft/fbtft-core.c
>> +++ b/drivers/staging/fbtft/fbtft-core.c
>> @@ -365,9 +365,9 @@ static int fbtft_fb_setcolreg(unsigned int regno, 
>> unsigned int red,
>>       unsigned int val;
>>       int ret = 1;
>> -    dev_dbg(info->dev,
>> -        "%s(regno=%u, red=0x%X, green=0x%X, blue=0x%X, trans=0x%X)\n",
>> -        __func__, regno, red, green, blue, transp);
>> +    fb_dbg(info,
>> +           "regno=%u, red=0x%X, green=0x%X, blue=0x%X, trans=0x%X\n",
>> +           regno, red, green, blue, transp);
>>       switch (info->fix.visual) {
>>       case FB_VISUAL_TRUECOLOR:
>> @@ -391,8 +391,7 @@ static int fbtft_fb_blank(int blank, struct 
>> fb_info *info)
>>       struct fbtft_par *par = info->par;
>>       int ret = -EINVAL;
>> -    dev_dbg(info->dev, "%s(blank=%d)\n",
>> -        __func__, blank);
>> +    fb_dbg(info, "blank=%d\n", blank);
>>       if (!par->fbtftops.blank)
>>           return ret;
>> @@ -793,11 +792,11 @@ int fbtft_register_framebuffer(struct fb_info 
>> *fb_info)
>>       if (spi)
>>           sprintf(text2, ", spi%d.%d at %d MHz", spi->controller- 
>> >bus_num,
>>               spi_get_chipselect(spi, 0), spi->max_speed_hz / 1000000);
>> -    dev_info(fb_info->dev,
>> -         "%s frame buffer, %dx%d, %d KiB video memory%s, fps=%lu%s\n",
>> -         fb_info->fix.id, fb_info->var.xres, fb_info->var.yres,
>> -         fb_info->fix.smem_len >> 10, text1,
>> -         HZ / fb_info->fbdefio->delay, text2);
>> +    fb_info(fb_info,
>> +        "%s frame buffer, %dx%d, %d KiB video memory%s, fps=%lu%s\n",
>> +        fb_info->fix.id, fb_info->var.xres, fb_info->var.yres,
>> +        fb_info->fix.smem_len >> 10, text1,
>> +        HZ / fb_info->fbdefio->delay, text2);
> 
> As discussed before, this should become fb_dbg().  Drivers should not 
> print status reports unless they do not work as expected.

Agree - I will send 2 patches(series) as per feedback 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 downgrades the framebuffer
     registration message to debug level.

> Best regards
> Thomas
> 
>>       /* Turn on backlight if available */
>>       if (fb_info->bl_dev) {
>