drivers/pci/vgaarb.c

3  * vgaarb.c: Implements VGA arbitration. For details refer to
39  * We keep a list of all VGA devices in the system to speed
117  * vga_default_device - return the default VGA device, for vgacon
120  * rather dumb and will probably only work properly on single VGA card
123  * If your VGA default device is not PCI, you'll have to return NULL here.
126  * the VGA default device if that is possible. This may be a problem with
127  * real _ISA_ VGA cards, in addition to a PCI one. I don't know at this
148  * vga_remove_vgacon - deactivate VGA console
150  * Unbind and unregister vgacon in case pdev is the default VGA device.
151  * Can be called by GPU drivers on initialization to make sure VGA register
173 	vgaarb_info(&pdev->dev, "deactivate vga console\n");  in vga_remove_vgacon()
194  * If we don't ever use VGA arbitration, we should avoid turning off
196  * device not being VGA.
201 	 * Inform all GPUs in the system that VGA arbitration has occurred  in vga_check_first_use()
262 		 * VGA forwarding on P2P bridges.  in __vga_tryget()
401  * vga_get - acquire & lock VGA resources
402  * @pdev: PCI device of the VGA card or NULL for the system default
406  * Acquire VGA resources for the given card and mark those resources
412  * The arbiter will first look for all VGA cards that might conflict and disable
413  * their IOs and/or Memory access, including VGA forwarding on P2P bridges if
416  * enabled on the card (including VGA forwarding on parent P2P bridges if any).
420  * bridges don't differentiate VGA memory and IO afaik). You can indicate
428  * On success, release the VGA resource again with vga_put().
487  * vga_tryget - try to acquire & lock legacy VGA resources
488  * @pdev: PCI device of VGA card or NULL for system default
495  * On success, release the VGA resource again with vga_put().
528  * vga_put - release lock on legacy VGA resources
529  * @pdev: PCI device of VGA card or NULL for system default
601  * Return true if vgadev is a better default VGA device than the best one
611 	 * We select the default VGA device in this order:  in vga_is_boot_device()
613 	 *   Legacy VGA device (owns VGA_RSRC_LEGACY_MASK)  in vga_is_boot_device()
632 	 * A legacy VGA device has MEM and IO enabled and any bridges  in vga_is_boot_device()
648 	 * If we haven't found a legacy VGA device, accept a non-legacy  in vga_is_boot_device()
651 	 * use legacy VGA resources.  Prefer an integrated GPU over others.  in vga_is_boot_device()
680 	 * other VGA devices, it is the best candidate so far.  in vga_is_boot_device()
689  * Rules for using a bridge to control a VGA descendant decoding: if a bridge
690  * has only one VGA descendant then it can be used to control the VGA routing
692  * control it. If a bridge has a direct VGA descendant, but also have a sub-
693  * bridge VGA descendant then we cannot use that bridge to control the direct
694  * VGA descendant. So for every device we register, we need to iterate all
770 		vgaarb_err(&pdev->dev, "failed to allocate VGA arbiter data\n");  in vga_arbiter_add_pci_device()
803 	/* Check if VGA cycles can get down to us */  in vga_arbiter_add_pci_device()
820 		vgaarb_info(&pdev->dev, "setting as boot VGA device%s\n",  in vga_arbiter_add_pci_device()
831 	vgaarb_info(&pdev->dev, "VGA device added: decodes=%s,owns=%s,locks=%s\n",  in vga_arbiter_add_pci_device()
886 	vgaarb_info(dev, "VGA decodes changed: olddecodes=%s,decodes=%s:owns=%s\n",  in vga_update_device_decodes()
942  * @pdev: PCI device of the VGA card
945  * Indicate to the arbiter if the card decodes legacy VGA IOs, legacy VGA
958  * vga_client_register - register or unregister a VGA arbitration client
959  * @pdev: PCI device of the VGA client
960  * @set_decode: VGA decode change callback
964  * @set_decode callback: If a client can disable its GPU VGA resource, it
967  * Rationale: we cannot disable VGA decode resources unconditionally
969  * the VGA registers to control things like backlights etc. Hopefully newer
971  * special ACPI for this. The driver will get a callback when VGA
1004  *                attached to the default VGA device of the system.
1344 				vgaarb_dbg(&pdev->dev, "not a VGA device\n");  in vga_arb_write()
1467  * Callback any registered clients to let them know we have a change in VGA
1502 	/* Only deal with VGA class devices */  in pci_notify()
1509 	 * for the cases of hot-pluggable VGA cards.  in pci_notify()
1549 	/* Add all VGA class PCI devices by default */  in vga_arb_device_init()