diff options
Diffstat (limited to 'src/mesa/drivers/dri/i965/gen7_l3_state.c')
| -rw-r--r-- | src/mesa/drivers/dri/i965/gen7_l3_state.c | 61 |
1 files changed, 57 insertions, 4 deletions
diff --git a/src/mesa/drivers/dri/i965/gen7_l3_state.c b/src/mesa/drivers/dri/i965/gen7_l3_state.c index 79569358914..b63e61ca8f0 100644 --- a/src/mesa/drivers/dri/i965/gen7_l3_state.c +++ b/src/mesa/drivers/dri/i965/gen7_l3_state.c @@ -59,7 +59,9 @@ struct brw_l3_config { }; /** - * IVB/HSW validated L3 configurations. + * IVB/HSW validated L3 configurations. The first entry will be used as + * default by gen7_restore_default_l3_config(), otherwise the ordering is + * unimportant. */ static const struct brw_l3_config ivb_l3_configs[] = { /* SLM URB ALL DC RO IS C T */ @@ -81,7 +83,7 @@ static const struct brw_l3_config ivb_l3_configs[] = { }; /** - * VLV validated L3 configurations. + * VLV validated L3 configurations. \sa ivb_l3_configs. */ static const struct brw_l3_config vlv_l3_configs[] = { /* SLM URB ALL DC RO IS C T */ @@ -97,7 +99,7 @@ static const struct brw_l3_config vlv_l3_configs[] = { }; /** - * BDW validated L3 configurations. + * BDW validated L3 configurations. \sa ivb_l3_configs. */ static const struct brw_l3_config bdw_l3_configs[] = { /* SLM URB ALL DC RO IS C T */ @@ -113,7 +115,7 @@ static const struct brw_l3_config bdw_l3_configs[] = { }; /** - * CHV/SKL validated L3 configurations. + * CHV/SKL validated L3 configurations. \sa ivb_l3_configs. */ static const struct brw_l3_config chv_l3_configs[] = { /* SLM URB ALL DC RO IS C T */ @@ -520,3 +522,54 @@ const struct brw_tracked_state gen7_l3_state = { }, .emit = emit_l3_state }; + +/** + * Hack to restore the default L3 configuration. + * + * This will be called at the end of every batch in order to reset the L3 + * configuration to the default values for the time being until the kernel is + * fixed. Until kernel commit 6702cf16e0ba8b0129f5aa1b6609d4e9c70bc13b + * (included in v4.1) we would set the MI_RESTORE_INHIBIT bit when submitting + * batch buffers for the default context used by the DDX, which meant that any + * context state changed by the GL would leak into the DDX, the assumption + * being that the DDX would initialize any state it cares about manually. The + * DDX is however not careful enough to program an L3 configuration + * explicitly, and it makes assumptions about it (URB size) which won't hold + * and cause it to misrender if we let our L3 set-up to leak into the DDX. + * + * Since v4.1 of the Linux kernel the default context is saved and restored + * normally, so it's far less likely for our L3 programming to interfere with + * other contexts -- In fact restoring the default L3 configuration at the end + * of the batch will be redundant most of the time. A kind of state leak is + * still possible though if the context making assumptions about L3 state is + * created immediately after our context was active (e.g. without the DDX + * default context being scheduled in between) because at present the DRM + * doesn't fully initialize the contents of newly created contexts and instead + * sets the MI_RESTORE_INHIBIT flag causing it to inherit the state from the + * last active context. + * + * It's possible to realize such a scenario if, say, an X server (or a GL + * application using an outdated non-L3-aware Mesa version) is started while + * another GL application is running and happens to have modified the L3 + * configuration, or if no X server is running at all and a GL application + * using a non-L3-aware Mesa version is started after another GL application + * ran and modified the L3 configuration -- The latter situation can actually + * be reproduced easily on IVB in our CI system. + */ +void +gen7_restore_default_l3_config(struct brw_context *brw) +{ + const struct brw_device_info *devinfo = brw->intelScreen->devinfo; + /* For efficiency assume that the first entry of the array matches the + * default configuration. + */ + const struct brw_l3_config *const cfg = get_l3_configs(devinfo); + assert(cfg == get_l3_config(devinfo, + get_default_l3_weights(devinfo, false, false))); + + if (cfg != brw->l3.config && brw->can_do_pipelined_register_writes) { + setup_l3_config(brw, cfg); + update_urb_size(brw, cfg); + brw->l3.config = cfg; + } +} |