On 6/27/2016 9:26 PM, Tvrtko Ursulin wrote:
On 27/06/16 16:32, Goel, Akash wrote:
On 6/27/2016 8:30 PM, Tvrtko Ursulin wrote:
On 27/06/16 13:16, akash.goel@xxxxxxxxx wrote:
From: Sagar Arun Kamble <sagar.a.kamble@xxxxxxxxx>
GuC Log buffer allocation was tied up with verbosity level kernel
parameter
i915.guc_log_level. User could be given a provision to enable
logging at
runtime and not necessarily during load time only. This patch will
perform
allocation of shared log buffer always but will initially enable
logging on
GuC side through init params based on i915.guc_log_level.
Signed-off-by: Sagar Arun Kamble <sagar.a.kamble@xxxxxxxxx>
Signed-off-by: Akash Goel <akash.goel@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_guc_submission.c | 3 ---
drivers/gpu/drm/i915/intel_guc_loader.c | 8 +++++---
2 files changed, 5 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c
b/drivers/gpu/drm/i915/i915_guc_submission.c
index 355b647..28a810f 100644
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -826,9 +826,6 @@ static void guc_create_log(struct intel_guc *guc)
unsigned long offset;
uint32_t size, flags;
- if (i915.guc_log_level < GUC_LOG_VERBOSITY_MIN)
- return;
-
if (i915.guc_log_level > GUC_LOG_VERBOSITY_MAX)
i915.guc_log_level = GUC_LOG_VERBOSITY_MAX;
diff --git a/drivers/gpu/drm/i915/intel_guc_loader.c
b/drivers/gpu/drm/i915/intel_guc_loader.c
index 8fe96a2..db3c897 100644
--- a/drivers/gpu/drm/i915/intel_guc_loader.c
+++ b/drivers/gpu/drm/i915/intel_guc_loader.c
@@ -173,11 +173,13 @@ static void set_guc_init_params(struct
drm_i915_private *dev_priv)
params[GUC_CTL_FEATURE] |= GUC_CTL_DISABLE_SCHEDULER |
GUC_CTL_VCS2_ENABLED;
- if (i915.guc_log_level >= 0) {
- params[GUC_CTL_LOG_PARAMS] = guc->log_flags;
+ params[GUC_CTL_LOG_PARAMS] = guc->log_flags;
+
+ if (i915.guc_log_level >= 0)
params[GUC_CTL_DEBUG] =
i915.guc_log_level << GUC_LOG_VERBOSITY_SHIFT;
- }
+ else
+ params[GUC_CTL_DEBUG] = GUC_LOG_DISABLED;
if (guc->ads_obj) {
u32 ads = (u32)i915_gem_obj_ggtt_offset(guc->ads_obj)
I did not manage to understand what is the benefit of always allocating
the log buffer? If the user never enables logging it just wasted 11
pages of memory, correct?
Yes if User never enables the logging at runtime, 11 RAM pages will be
wasted.
Currently the pages are permanently pinned in GGTT also.
The GGTT address of log buffer is passed in the GuC firmware init
params, at firmware loading time.
Probably this can be circumvented, if pages can be pinned right before
enabling logging (but using the same GGTT address).
Looking at the later patches in the series, could you instead create the
log buffer when logging is enabled via debugfs or implicitly via the
relayfs access?
Or is the problem then that you would then have to reset the GuC to
activate it?
Yes GuC would have to be reset & firmware needs to be reloaded to pass
the log buffer address.
Right, as minimum I think commit message needs to explain that. The
current explanation does not hold anyway since it is not possible to
enable it via modifying the module parameter.
Right, there should have been an explanation citing the constraint in
late allocation of log buffer when logging is enabled.
Sorry for missing.
Btw have you considered keeping the module param as a global GuC logging
enable and adding new code on top? So keep the current code to only
allocate the buffer when module param is set, and then if it isn't fail
the later userspace triggered attempts to start the logging (in debugfs
or relayfs)?
Yes that was considered, keeping module param as the master control and
allowing disable/enable of logging at runtime (through debugfs) only
when module param is set at boot time.
IIRC there was a request from Validation to keep logging control
independent of boot time value of module param. So even if system
booted with guc_log_level as -1, still allow the logging to be enabled
at runtime later, through a debugfs interface 'i915_guc_log_control'.
Best regards
Akash
Regards,
Tvrtko
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