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* PowerPC agpmode issues
@ 2016-02-05  2:47 Mike
  2016-02-05  7:49 ` Denis Kirjanov
                   ` (2 more replies)
  0 siblings, 3 replies; 33+ messages in thread
From: Mike @ 2016-02-05  2:47 UTC (permalink / raw)
  To: Pranith Kumar; +Cc: Aneesh Kumar K.V, open list:LINUX FOR POWERPC...

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Hi.
Managed to get the Radeon R300 running on mesa 11.1.1 with an old 2013
patch from Michel Dànzer, next problem is of course enabling agpmode,
running with pci-mode with radeon.agpmode=-1 works, but is of course slow,
and seems to load the cpu a lot.

Upon initial investigation i could not initially believe agp could be this
this broken for this long, until i found this.
 "committed with Ben Skeggs on Feb 26, 2013"
https://github.com/DespairFactor/bullhead/commit/650e1203c11354ba84d69ba445abc0efcfe3890a
http://lxr.free-electrons.com/source/drivers/gpu/drm/nouveau/nouveau_agp.c?v=4.2
#ifdef __powerpc__
/* Disable AGP by default on all PowerPC machines for
* now -- At least some UniNorth-2 AGP bridges are
* known to be broken: DMA from the host to the card
* works just fine, but writeback from the card to the
* host goes straight to memory untranslated bypassing
* the GATT somehow, making them quite painful to deal
* with...
*/
if (nouveau_agpmode == -1)
return false;
#endif

 and now later this:
https://github.com/torvalds/linux/blob/master/drivers/gpu/drm/nouveau/nvkm/subdev/pci/agp.c
#ifdef __powerpc__
/* Disable AGP by default on all PowerPC machines for now -- At
* least some UniNorth-2 AGP bridges are known to be broken:
* DMA from the host to the card works just fine, but writeback
* from the card to the host goes straight to memory
* untranslated bypassing that GATT somehow, making them quite
* painful to deal with...
*/
mode = 0;
#endif

All seems to point to serious issues had around the time of change to ums
to kms and a serious regression hitting the linux kernel? No?

Cheers
-Mike

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^ permalink raw reply	[flat|nested] 33+ messages in thread

end of thread, other threads:[~2016-10-09  7:50 UTC | newest]

Thread overview: 33+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-02-05  2:47 PowerPC agpmode issues Mike
2016-02-05  7:49 ` Denis Kirjanov
2016-02-05 14:42   ` Mike
2016-02-05 14:32 ` Herminio Hernandez Jr. 
2016-02-05 14:44   ` Mike
2016-02-05 17:51     ` Herminio Hernandez, Jr.
2016-02-05 18:06       ` Mike
2016-02-05 18:08         ` Herminio Hernandez, Jr.
2016-02-05 19:44           ` Mike
2016-02-05 19:46             ` Herminio Hernandez, Jr.
2016-02-05 19:59               ` Mike
2016-02-05 20:10                 ` Herminio Hernandez, Jr.
2016-08-25  3:09   ` Mike
2016-08-25  5:34     ` Mathieu Malaterre
2016-08-25 10:54     ` Benjamin Herrenschmidt
     [not found]       ` <57DF23C4.20508@gmail.com>
2016-09-19  9:13         ` Herminio Hernandez, Jr.
2016-09-19 10:38           ` Benjamin Herrenschmidt
2016-09-19 19:30             ` Herminio Hernandez, Jr.
2016-09-19 12:36           ` Mathieu Malaterre
2016-09-20  3:05             ` Michel Dänzer
2016-09-20  3:43               ` Herminio Hernandez, Jr.
2016-09-20  6:20                 ` Michel Dänzer
2016-09-21  6:20                   ` Herminio Hernandez, Jr.
2016-10-08 19:05                     ` Herminio Hernandez, Jr.
2016-10-09  7:49                       ` Benjamin Herrenschmidt
2016-02-08  9:53 ` Michel Dänzer
2016-02-08 12:09   ` Mike
2016-02-08 12:41   ` Boris Reinhard
2016-02-08 13:28     ` Mike
2016-02-09  1:41       ` Michel Dänzer
2016-02-09  2:27         ` Mike
2016-02-09 11:52           ` Gerhard Pircher
2016-02-09 12:15             ` luigi burdo

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