[PATCH v2] fbdev/hga: Request memory region before ioremap

[PATCH v2] fbdev/hga: Request memory region before ioremap

[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>
---
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/
[1]: https://lore.kernel.org/all/5f9749ba-18a8-4b6b-a6e7-a011a3871bfb@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..fffd34141f8d 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")) {
+		pr_err("hgafb: 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;
 
-- 
2.53.0

Re: [PATCH v2] fbdev/hga: Request memory region before ioremap

[Thomas Zimmermann]

Hi

Am 10.03.26 um 12:38 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>
> ---
> 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/
> [1]: https://lore.kernel.org/all/5f9749ba-18a8-4b6b-a6e7-a011a3871bfb@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..fffd34141f8d 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")) {
> +		pr_err("hgafb: cannot reserve video memory at 0xb0000\n");

dev_err() with pdev->dev please.

The rest looks good.

Best regards
Thomas

> +		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)