| Message ID | 1470983123-22127-18-git-send-email-akash.goel@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 12/08/16 07:25, akash.goel@intel.com wrote: > From: Akash Goel <akash.goel@intel.com> > > Host needs to sample the GuC log buffer on every flush interrupt from GuC. > To ensure that we always get the up-to-date data from log buffer, its > better to access the buffer through an uncached CPU mapping. Also the way > buffer is accessed from GuC & Host side, manually doing cache flush may > not be effective always if cached CPU mapping is used. > Though there could be some performance implication with Uncached read, but > reliability of data will be ensured. > > v2: Rebase. > > v3: Rebase. > > Signed-off-by: Akash Goel <akash.goel@intel.com> > --- > drivers/gpu/drm/i915/i915_guc_submission.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c > index 1d58d36..1818343 100644 > --- a/drivers/gpu/drm/i915/i915_guc_submission.c > +++ b/drivers/gpu/drm/i915/i915_guc_submission.c > @@ -1002,8 +1002,6 @@ static void guc_read_update_log_buffer(struct intel_guc *guc) > dst_data_ptr += buffer_size; > } > > - /* FIXME: invalidate/flush for log buffer needed */ > - > /* Update the read pointer in the shared log buffer */ > log_buffer_state->read_ptr = write_offset; > > @@ -1177,8 +1175,11 @@ static int guc_create_log_extras(struct intel_guc *guc) > return 0; > > if (!guc->log.buf_addr) { > - /* Create a vmalloc mapping of log buffer pages */ > - vaddr = i915_gem_object_pin_map(guc->log.obj, I915_MAP_WB); > + /* Create a WC (Uncached for read) vmalloc mapping of log > + * buffer pages, so that we can directly get the data > + * (up-to-date) from memory. > + */ > + vaddr = i915_gem_object_pin_map(guc->log.obj, I915_MAP_WC); > if (IS_ERR(vaddr)) { > ret = PTR_ERR(vaddr); > DRM_ERROR("Couldn't map log buffer pages %d\n", ret); > Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Hopefully no one applies this without 19/20. :) Regards, Tvrtko
diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c index 1d58d36..1818343 100644 --- a/drivers/gpu/drm/i915/i915_guc_submission.c +++ b/drivers/gpu/drm/i915/i915_guc_submission.c @@ -1002,8 +1002,6 @@ static void guc_read_update_log_buffer(struct intel_guc *guc) dst_data_ptr += buffer_size; } - /* FIXME: invalidate/flush for log buffer needed */ - /* Update the read pointer in the shared log buffer */ log_buffer_state->read_ptr = write_offset; @@ -1177,8 +1175,11 @@ static int guc_create_log_extras(struct intel_guc *guc) return 0; if (!guc->log.buf_addr) { - /* Create a vmalloc mapping of log buffer pages */ - vaddr = i915_gem_object_pin_map(guc->log.obj, I915_MAP_WB); + /* Create a WC (Uncached for read) vmalloc mapping of log + * buffer pages, so that we can directly get the data + * (up-to-date) from memory. + */ + vaddr = i915_gem_object_pin_map(guc->log.obj, I915_MAP_WC); if (IS_ERR(vaddr)) { ret = PTR_ERR(vaddr); DRM_ERROR("Couldn't map log buffer pages %d\n", ret);