2  * vgaarb.c: Implements the VGA arbitration. For details refer to
58  * We keep a list of all vga devices in the system to speed
139  * vga_default_device - return the default VGA device, for vgacon
143  * vga card setups and/or x86 platforms.
145  * If your VGA default device is not PCI, you'll have to return
148  * hooks for enabling/disabling the VGA default device if that is
149  * possible. This may be a problem with real _ISA_ VGA cards, in
178 /* If we don't ever use VGA arb we should avoid
180    confused about the boot device not being VGA */
184 	 * VGA arb has occurred and to try and disable resources  in vga_check_first_use()
247 		 * VGA forwarding on P2P bridges  in __vga_tryget()
383  * vga_get - acquire & locks VGA resources
384  * @pdev: pci device of the VGA card or NULL for the system default
388  * This function acquires VGA resources for the given card and mark those
394  * The arbiter will first look for all VGA cards that might conflict and disable
395  * their IOs and/or Memory access, including VGA forwarding on P2P bridges if
398  * enabled on the card (including VGA forwarding on parent P2P bridges if any).
402  * bridges don't differentiate VGA memory and IO afaik). You can indicate
410  * On success, release the VGA resource again with vga_put().
469  * vga_tryget - try to acquire & lock legacy VGA resources
470  * @pdev: pci devivce of VGA card or NULL for system default
477  * On success, release the VGA resource again with vga_put().
511  * vga_put - release lock on legacy VGA resources
512  * @pdev: pci device of VGA card or NULL for system default
541  * Rules for using a bridge to control a VGA descendant decoding: if a bridge
542  * has only one VGA descendant then it can be used to control the VGA routing
544  * control it. If a bridge has a direct VGA descendant, but also have a sub-
545  * bridge VGA descendant then we cannot use that bridge to control the direct
546  * VGA descendant. So for every device we register, we need to iterate all
613 	/* Only deal with VGA class devices */  in vga_arbiter_add_pci_device()
620 		vgaarb_err(&pdev->dev, "failed to allocate VGA arbiter data\n");  in vga_arbiter_add_pci_device()
651 	/* Check if VGA cycles can get down to us */  in vga_arbiter_add_pci_device()
667 	/* Deal with VGA default device. Use first enabled one  in vga_arbiter_add_pci_device()
672 		vgaarb_info(&pdev->dev, "setting as boot VGA device\n");  in vga_arbiter_add_pci_device()
681 	vgaarb_info(&pdev->dev, "VGA device added: decodes=%s,owns=%s,locks=%s\n",  in vga_arbiter_add_pci_device()
741 	vgaarb_info(dev, "changed VGA decodes: olddecodes=%s,decodes=%s:owns=%s\n",  in vga_update_device_decodes()
801  * vga_client_register - register or unregister a VGA arbitration client
802  * @pdev: pci device of the VGA client
805  * @set_vga_decode: vga decode change callback
809  * @irq_set_state callback: If a client can't disable its GPUs VGA
813  * @set_vga_decode callback: If a client can disable its GPU VGA resource, it
816  * Rationale: we cannot disable VGA decode resources unconditionally some single
817  * GPU laptops seem to require ACPI or BIOS access to the VGA registers to
820  * driver will get a callback when VGA arbitration is first used by userspace
863  *                attached to the default VGA device of the system.
970 	 * away), and allows access to vga list  in vga_arb_read()
1210 				vgaarb_dbg(&pdev->dev, "not a VGA device\n");  in vga_arb_write()
1339  * change in VGA cards
1377 	 * cases of hotplugable vga cards. */  in pci_notify()
1460 				vgaarb_info(dev, "setting as boot device (VGA legacy resources not available)\n");  in vga_arb_select_default_device()
1472 			vgaarb_info(dev, "setting as boot device (VGA legacy resources not available)\n");  in vga_arb_select_default_device()
1490 	/* We add all PCI devices satisfying VGA class in the arbiter by  in vga_arb_device_init()