Commit 15fced5b authored by Thomas Zimmermann's avatar Thomas Zimmermann
Browse files

fbdev: Remove conflict-handling code 



Remove the call to do_remove_conflicting_framebuffers() from the
framebuffer registration. Aperture helpers take care of removing
conflicting devices. With all ownership information stored in the
aperture datastrcutures, remove remove_conflicting_framebuffers()
entirely.

This change also rectifies DRM generic-framebuffer registration, which
tried to unregister conflicting framebuffers, even though it's entirely
build on top of DRM.

v2:
	* remove internal aperture-overlap helpers, which are
	  now unused

Signed-off-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: default avatarJavier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220718072322.8927-12-tzimmermann@suse.de
parent 72a6a3e0

drivers/video/aperture.c

+0 −21
Original line number Diff line number Diff line
@@ -2,7 +2,6 @@ 


#include <linux/aperture.h>

#include <linux/device.h>

#include <linux/fb.h> /* for old fbdev helpers */

#include <linux/list.h>

#include <linux/mutex.h>

#include <linux/pci.h>
@@ -286,11 +285,6 @@ static void aperture_detach_devices(resource_size_t base, resource_size_t size) 
int aperture_remove_conflicting_devices(resource_size_t base, resource_size_t size,

					bool primary, const char *name)

{

#if IS_REACHABLE(CONFIG_FB)

	struct apertures_struct *a;

	int ret;

#endif



	/*

	 * If a driver asked to unregister a platform device registered by

	 * sysfb, then can be assumed that this is a driver for a display
@@ -312,21 +306,6 @@ int aperture_remove_conflicting_devices(resource_size_t base, resource_size_t si 
	if (primary)

		aperture_detach_devices(VGA_FB_PHYS_BASE, VGA_FB_PHYS_SIZE);



#if IS_REACHABLE(CONFIG_FB)

	a = alloc_apertures(1);

	if (!a)

		return -ENOMEM;



	a->ranges[0].base = base;

	a->ranges[0].size = size;



	ret = remove_conflicting_framebuffers(a, name, primary);

	kfree(a);



	if (ret)

		return ret;

#endif



	return 0;

}

EXPORT_SYMBOL(aperture_remove_conflicting_devices);

drivers/video/fbdev/core/fbmem.c

+0 −136
Original line number Diff line number Diff line
@@ -1526,102 +1526,6 @@ static int fb_check_foreignness(struct fb_info *fi) 
	return 0;

}



static bool apertures_overlap(struct aperture *gen, struct aperture *hw)

{

	/* is the generic aperture base the same as the HW one */

	if (gen->base == hw->base)

		return true;

	/* is the generic aperture base inside the hw base->hw base+size */

	if (gen->base > hw->base && gen->base < hw->base + hw->size)

		return true;

	return false;

}



static bool fb_do_apertures_overlap(struct apertures_struct *gena,

				    struct apertures_struct *hwa)

{

	int i, j;

	if (!hwa || !gena)

		return false;



	for (i = 0; i < hwa->count; ++i) {

		struct aperture *h = &hwa->ranges[i];

		for (j = 0; j < gena->count; ++j) {

			struct aperture *g = &gena->ranges[j];

			printk(KERN_DEBUG "checking generic (%llx %llx) vs hw (%llx %llx)\n",

				(unsigned long long)g->base,

				(unsigned long long)g->size,

				(unsigned long long)h->base,

				(unsigned long long)h->size);

			if (apertures_overlap(g, h))

				return true;

		}

	}



	return false;

}



static void do_unregister_framebuffer(struct fb_info *fb_info);



static void do_remove_conflicting_framebuffers(struct apertures_struct *a,

					       const char *name, bool primary)

{

	int i;



restart_removal:

	/* check all firmware fbs and kick off if the base addr overlaps */

	for_each_registered_fb(i) {

		struct apertures_struct *gen_aper;

		struct device *device;



		if (!(registered_fb[i]->flags & FBINFO_MISC_FIRMWARE))

			continue;



		gen_aper = registered_fb[i]->apertures;

		device = registered_fb[i]->device;

		if (fb_do_apertures_overlap(gen_aper, a) ||

			(primary && gen_aper && gen_aper->count &&

			 gen_aper->ranges[0].base == VGA_FB_PHYS_BASE)) {



			printk(KERN_INFO "fb%d: switching to %s from %s\n",

			       i, name, registered_fb[i]->fix.id);



			/*

			 * If we kick-out a firmware driver, we also want to remove

			 * the underlying platform device, such as simple-framebuffer,

			 * VESA, EFI, etc. A native driver will then be able to

			 * allocate the memory range.

			 *

			 * If it's not a platform device, at least print a warning. A

			 * fix would add code to remove the device from the system. For

			 * framebuffers without any Linux device, print a warning as

			 * well.

			 */

			if (!device) {

				pr_warn("fb%d: no device set\n", i);

				do_unregister_framebuffer(registered_fb[i]);

			} else if (dev_is_platform(device)) {

				/*

				 * Drop the lock because if the device is unregistered, its

				 * driver will call to unregister_framebuffer(), that takes

				 * this lock.

				 */

				mutex_unlock(&registration_lock);

				platform_device_unregister(to_platform_device(device));

				mutex_lock(&registration_lock);

			} else {

				pr_warn("fb%d: cannot remove device\n", i);

				do_unregister_framebuffer(registered_fb[i]);

			}

			/*

			 * Restart the removal loop now that the device has been

			 * unregistered and its associated framebuffer gone.

			 */

			goto restart_removal;

		}

	}

}



static int do_register_framebuffer(struct fb_info *fb_info)

{

	int i;
@@ -1630,10 +1534,6 @@ static int do_register_framebuffer(struct fb_info *fb_info) 
	if (fb_check_foreignness(fb_info))

		return -ENOSYS;



	do_remove_conflicting_framebuffers(fb_info->apertures,

					   fb_info->fix.id,

					   fb_is_primary_device(fb_info));



	if (num_registered_fb == FB_MAX)

		return -ENXIO;
@@ -1778,42 +1678,6 @@ static int fb_aperture_acquire_for_platform_device(struct fb_info *fb_info) 
	return ret;

}



/**

 * remove_conflicting_framebuffers - remove firmware-configured framebuffers

 * @a: memory range, users of which are to be removed

 * @name: requesting driver name

 * @primary: also kick vga16fb if present

 *

 * This function removes framebuffer devices (initialized by firmware/bootloader)

 * which use memory range described by @a. If @a is NULL all such devices are

 * removed.

 */

int remove_conflicting_framebuffers(struct apertures_struct *a,

				    const char *name, bool primary)

{

	bool do_free = false;



	if (!a) {

		a = alloc_apertures(1);

		if (!a)

			return -ENOMEM;



		a->ranges[0].base = 0;

		a->ranges[0].size = ~0;

		do_free = true;

	}



	mutex_lock(&registration_lock);

	do_remove_conflicting_framebuffers(a, name, primary);

	mutex_unlock(&registration_lock);



	if (do_free)

		kfree(a);



	return 0;

}

EXPORT_SYMBOL(remove_conflicting_framebuffers);



/**

 *	register_framebuffer - registers a frame buffer device

 *	@fb_info: frame buffer info structure

include/linux/fb.h

+0 −2
Original line number Diff line number Diff line
@@ -615,8 +615,6 @@ extern ssize_t fb_sys_write(struct fb_info *info, const char __user *buf, 
/* drivers/video/fbmem.c */

extern int register_framebuffer(struct fb_info *fb_info);

extern void unregister_framebuffer(struct fb_info *fb_info);

extern int remove_conflicting_framebuffers(struct apertures_struct *a,

					   const char *name, bool primary);

extern int fb_prepare_logo(struct fb_info *fb_info, int rotate);

extern int fb_show_logo(struct fb_info *fb_info, int rotate);

extern char* fb_get_buffer_offset(struct fb_info *info, struct fb_pixmap *buf, u32 size);