diff options
Diffstat (limited to 'drivers/gpu/drm')
| -rw-r--r-- | drivers/gpu/drm/xe/xe_gt_mcr.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/drivers/gpu/drm/xe/xe_gt_mcr.c b/drivers/gpu/drm/xe/xe_gt_mcr.c index 55b240a5eaa7..02afb313bfea 100644 --- a/drivers/gpu/drm/xe/xe_gt_mcr.c +++ b/drivers/gpu/drm/xe/xe_gt_mcr.c @@ -461,9 +461,16 @@ static u32 rw_with_mcr_steering(struct xe_gt *gt, struct xe_reg_mcr reg_mcr, } /* - * Always leave the hardware in multicast mode when doing reads - * (see comment about Wa_22013088509 below) and only change it - * to unicast mode when doing writes of a specific instance. + * Always leave the hardware in multicast mode when doing reads and only + * change it to unicast mode when doing writes of a specific instance. + * + * The setting of the multicast/unicast bit usually wouldn't matter for + * read operations (which always return the value from a single register + * instance regardless of how that bit is set), but some platforms may + * have workarounds requiring us to remain in multicast mode for reads, + * e.g. Wa_22013088509 on PVC. There's no real downside to this, so + * we'll just go ahead and do so on all platforms; we'll only clear the + * multicast bit from the mask when explicitly doing a write operation. * * No need to save old steering reg value. */ |