problème sortie veille ou hibernation

bonjour, je rencontre un problème non pas systématique mais récurrent sous Debian Jessie, l’écran est figé à la sortie de la mise en veille ou hibernation, je suis obligé de forcer un re-démarrage.

le problème semble venir de nouveau et/ou conflit adresse mémoire ACPI
dans syslog:

Dec 5 08:19:49 debian kernel: [75198.765142] nouveau E[ PGRAPH][0000:01:00.0] PGRAPH TLB flush idle timeout fail Dec 5 08:19:49 debian kernel: [75198.765142] nouveau E[ PGRAPH][0000:01:00.0] PGRAPH_STATUS : 0x01100001 BUSY TPC_PROP ROP Dec 5 08:19:49 debian kernel: [75198.765142] nouveau E[ PGRAPH][0000:01:00.0] PGRAPH_VSTATUS0: 0x00000000 Dec 5 08:19:49 debian kernel: [75198.765142] nouveau E[ PGRAPH][0000:01:00.0] PGRAPH_VSTATUS1: 0x00000028 Dec 5 08:19:49 debian kernel: [75198.765142] nouveau E[ PGRAPH][0000:01:00.0] PGRAPH_VSTATUS2: 0x00200000 ROP

ainsi que:

Dec 5 08:25:00 debian kernel: [ 16.751570] ACPI Warning: SystemIO range 0x0000000000000428-0x000000000000042f conflicts with OpRegion 0x0000000000000400-0x000000000000047f (\PMBA) (20140424/utaddress-258) Dec 5 08:25:00 debian kernel: [ 16.751582] ACPI Warning: SystemIO range 0x0000000000000530-0x000000000000053f conflicts with OpRegion 0x0000000000000500-0x000000000000053b (\GPIO) (20140424/utaddress-258) Dec 5 08:25:00 debian kernel: [ 16.751587] ACPI Warning: SystemIO range 0x0000000000000500-0x000000000000052f conflicts with OpRegion 0x0000000000000500-0x000000000000053b (\GPIO) (20140424/utaddress-258) Dec 5 08:25:00 debian kernel: [ 17.822581] ACPI Warning: \_SB_.PCI0.PEGP.VGA_._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20140424/nsarguments-95) Dec 5 08:25:00 debian kernel: [ 17.952345] ACPI Warning: \_SB_.PCI0.PEGP.VGA_._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20140424/nsarguments-95)

lspci | grep VGA