On 8/15/2016 2:50 PM, Tvrtko Ursulin wrote:
On 12/08/16 17:31, Goel, Akash wrote:
On 8/12/2016 9:52 PM, Tvrtko Ursulin wrote:
On 12/08/16 07:25, akash.goel@xxxxxxxxx wrote:
From: Akash Goel <akash.goel@xxxxxxxxx>
As per the current i915 Driver load sequence, debugfs registration is
done
at the end and so the relay channel debugfs file is also created after
that
but the GuC firmware is loaded much earlier in the sequence.
As a result Driver could miss capturing the boot-time logs of GuC
firmware
if there are flush interrupts from the GuC side.
Relay has a provision to support early logging where initially only
relay
channel can be created, to have buffers for storing logs, and later on
channel can be associated with a debugfs file at appropriate time.
Have availed that, which allows Driver to capture boot time logs also,
which can be collected once Userspace comes up.
Suggested-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Akash Goel <akash.goel@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_guc_submission.c | 61
+++++++++++++++++++++---------
1 file changed, 44 insertions(+), 17 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c
b/drivers/gpu/drm/i915/i915_guc_submission.c
index af48f62..1c287d7 100644
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -1099,25 +1099,12 @@ static void guc_remove_log_relay_file(struct
intel_guc *guc)
relay_close(guc->log.relay_chan);
}
-static int guc_create_log_relay_file(struct intel_guc *guc)
+static int guc_create_relay_channel(struct intel_guc *guc)
{
struct drm_i915_private *dev_priv = guc_to_i915(guc);
struct rchan *guc_log_relay_chan;
- struct dentry *log_dir;
size_t n_subbufs, subbuf_size;
- /* For now create the log file in /sys/kernel/debug/dri/0 dir */
- log_dir = dev_priv->drm.primary->debugfs_root;
-
- /* If /sys/kernel/debug/dri/0 location do not exist, then
debugfs is
- * not mounted and so can't create the relay file.
- * The relay API seems to fit well with debugfs only.
It only needs a dentry, I don't see that it has to be a debugfs one.
Besides dentry, there are other requirements for using relay, which can
be met only for a debugfs file.
debugfs wasn't the preferred choice to place the log file, but had no
other option, as relay API is compatible with debugfs only.
What are those and
For availing relay there are 3 requirements :-
a) Need the associated ‘dentry’ pointer of the file, while opening the
relay channel.
b) Should be able to use 'relay_file_operations' fops for the file.
c) Set the 'i_private' field of file’s inode to the pointer of relay
channel buffer.
All the above 3 requirements can be met for a debugfs file in a
straightforward manner. But not all of them can be met for a file
created inside sysfs or if the file is created inside /dev as a
character device file.
should they be mentioned in the comment above?
Or should I mention them in the cover letter or commit message.
Best regards
Akash
Regards,
Tvrtko
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