Re: [PATCH v3] fbdev/hga: Request memory region before ioremap

[Thomas Zimmermann <tzimmermann@suse.de>]

Hi,

thanks for the patch. Let's hope there are no conflicts with other 
hardware.  IDK if anyone still uses this driver.

Am 10.03.26 um 13:30 schrieb Hardik Phalet:
> The driver calls ioremap() on the HGA video memory at 0xb0000 without
> first reserving the physical address range. This leaves the kernel
> resource tree incomplete and can cause silent conflicts with other
> drivers claiming the same range.
>
> Add a devm_request_mem_region() call before ioremap() in
> hga_card_detect() to reserve the memory region.
>
> Signed-off-by: Hardik Phalet <hardik.phalet@pm.me>

Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>

Best regards
Thomas

> ---
> Changes in v3:
> - Used dev_err() to log memory region request, based on another review
>    comment by Thomas [2].
> Changes in v2:
> - Used devm_request_mem_region instead of request_mem_region, based on a
> 	review comment by Thomas [1].
>
> v1: https://lore.kernel.org/all/20260310064124.602848-1-hardik.phalet@pm.me/
> v2: https://lore.kernel.org/all/20260310113810.789575-1-hardik.phalet@pm.me/
> [1]: https://lore.kernel.org/all/5f9749ba-18a8-4b6b-a6e7-a011a3871bfb@suse.de/
> [2]: https://lore.kernel.org/all/ec635591-c861-4aa8-a259-718690ddaa4e@suse.de/
>
>   drivers/video/fbdev/hgafb.c | 9 +++++++--
>   1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/video/fbdev/hgafb.c b/drivers/video/fbdev/hgafb.c
> index 14418aa3791a..d32fd1c5217c 100644
> --- a/drivers/video/fbdev/hgafb.c
> +++ b/drivers/video/fbdev/hgafb.c
> @@ -276,7 +276,7 @@ static void hga_blank(int blank_mode)
>   	spin_unlock_irqrestore(&hga_reg_lock, flags);
>   }
>   
> -static int hga_card_detect(void)
> +static int hga_card_detect(struct platform_device *pdev)
>   {
>   	int count = 0;
>   	void __iomem *p, *q;
> @@ -284,6 +284,11 @@ static int hga_card_detect(void)
>   
>   	hga_vram_len  = 0x08000;
>   
> +	if (!devm_request_mem_region(&pdev->dev, 0xb0000, hga_vram_len, "hgafb")) {
> +		dev_err(&pdev->dev, "cannot reserve video memory at 0xb0000\n");
> +		return -EBUSY;
> +	}
> +
>   	hga_vram = ioremap(0xb0000, hga_vram_len);
>   	if (!hga_vram)
>   		return -ENOMEM;
> @@ -568,7 +573,7 @@ static int hgafb_probe(struct platform_device *pdev)
>   	struct fb_info *info;
>   	int ret;
>   
> -	ret = hga_card_detect();
> +	ret = hga_card_detect(pdev);
>   	if (ret)
>   		return ret;
>   

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)