[PATCH v2] Fix loading of module radeonfb on PowerMac

[Tomi Valkeinen]

Hi,

On 14/11/16 21:59, Mathieu Malaterre wrote:
> When the linux kernel is build with (typical kernel ship with Debian
> installer):
> 
> CONFIG_FB_OF=y
> CONFIG_VT_HW_CONSOLE_BINDING=y
> CONFIG_FB_RADEON=m
> 
> The offb driver takes precedence over module radeonfb. It is then
> impossible to load the module, error reported is:
> 
> [   96.551486] radeonfb 0000:00:10.0: enabling device (0006 -> 0007)
> [   96.551526] radeonfb 0000:00:10.0: BAR 0: can't reserve [mem 0x98000000-0x9fffffff pref]
> [   96.551531] radeonfb (0000:00:10.0): cannot request region 0.
> [   96.551545] radeonfb: probe of 0000:00:10.0 failed with error -16
> 
> This patch reproduce the behavior of the module radeon, so as to make it
> possible to load radeonfb when offb is first loaded.
> 
> It should be noticed that `offb_destroy` is never called which explain the
> need to skip error detection on the radeon side.
> 
> Signed-off-by: Mathieu Malaterre <malat at debian.org>
> Link: https://bugs.debian.org/826629#57
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=119741
> Suggested-by: Lennart Sorensen <lsorense at csclub.uwaterloo.ca>
> ---

Please always have a changelog in patch new revisions. For individual
patches, you can insert the changes here.

>  drivers/video/fbdev/aty/radeon_base.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/drivers/video/fbdev/aty/radeon_base.c b/drivers/video/fbdev/aty/radeon_base.c
> index 218339a..84d634b 100644
> --- a/drivers/video/fbdev/aty/radeon_base.c
> +++ b/drivers/video/fbdev/aty/radeon_base.c
> @@ -2259,6 +2259,22 @@ static struct bin_attribute edid2_attr = {
>  	.read	= radeon_show_edid2,
>  };
>  
> +static int radeon_kick_out_firmware_fb(struct pci_dev *pdev)
> +{
> +	struct apertures_struct *ap;
> +
> +	ap = alloc_apertures(1);
> +	if (!ap)
> +		return -ENOMEM;
> +
> +	ap->ranges[0].base = pci_resource_start(pdev, 0);
> +	ap->ranges[0].size = pci_resource_len(pdev, 0);
> +
> +	remove_conflicting_framebuffers(ap, KBUILD_MODNAME, false);
> +	kfree(ap);
> +
> +	return 0;
> +}
>  
>  static int radeonfb_pci_register(struct pci_dev *pdev,
>  				 const struct pci_device_id *ent)
> @@ -2314,19 +2330,27 @@ static int radeonfb_pci_register(struct pci_dev *pdev,
>  	rinfo->fb_base_phys = pci_resource_start (pdev, 0);
>  	rinfo->mmio_base_phys = pci_resource_start (pdev, 2);
>  
> +	ret = radeon_kick_out_firmware_fb(pdev);
> +	if (ret)
> +		return ret;
> +
>  	/* request the mem regions */
>  	ret = pci_request_region(pdev, 0, "radeonfb framebuffer");
>  	if (ret < 0) {
>  		printk( KERN_ERR "radeonfb (%s): cannot request region 0.\n",
>  			pci_name(rinfo->pdev));
> +#ifndef CONFIG_PPC
>  		goto err_release_fb;
> +#endif

If this is not a problem on PPC, the kernel shouldn't print an error either.

>  	}
>  
>  	ret = pci_request_region(pdev, 2, "radeonfb mmio");
>  	if (ret < 0) {
>  		printk( KERN_ERR "radeonfb (%s): cannot request region 2.\n",
>  			pci_name(rinfo->pdev));
> +#ifndef CONFIG_PPC
>  		goto err_release_pci0;
> +#endif

Same here.

>  	}
>  
>  	/* map the regions */
> @@ -2511,10 +2535,12 @@ static int radeonfb_pci_register(struct pci_dev *pdev,
>  	iounmap(rinfo->mmio_base);
>  err_release_pci2:
>  	pci_release_region(pdev, 2);
> +#ifndef CONFIG_PPC
>  err_release_pci0:
>  	pci_release_region(pdev, 0);
>  err_release_fb:
>          framebuffer_release(info);
> +#endif
>  err_disable:
>  err_out:
>  	return ret;
> 

So I don't quite follow what's going on here. Why the CONFIG_PPC
conditionals? Is this problem only with OFFB and only with PPC?

And I think the code itself should have comments on this rather strange
behavior: the driver fails to get HW resources, but decides to ignore
the failure on PPC.

 Tomi

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