On 25/02/2022 09:44, Michal Wajdeczko wrote:
On 25.02.2022 06:03, Jordan Justen wrote:
John Harrison <john.c.harrison@xxxxxxxxx> writes:
On 2/22/2022 02:36, Jordan Justen wrote:
From: John Harrison <John.C.Harrison@xxxxxxxxx>
Implement support for fetching the hardware description table from the
GuC. The call is made twice - once without a destination buffer to
query the size and then a second time to fill in the buffer.
Note that the table is only available on ADL-P and later platforms.
v5 (of Jordan's posting):
* Various changes made by Jordan and recommended by Michal
- Makefile ordering
- Adjust "struct intel_guc_hwconfig hwconfig" comment
- Set Copyright year to 2022 in intel_guc_hwconfig.c/.h
- Drop inline from hwconfig_to_guc()
- Replace hwconfig param with guc in __guc_action_get_hwconfig()
- Move zero size check into guc_hwconfig_discover_size()
- Change comment to say zero size offset/size is needed to get size
- Add has_guc_hwconfig to devinfo and drop has_table()
- Change drm_err to notice in __uc_init_hw() and use %pe
Cc: Michal Wajdeczko <michal.wajdeczko@xxxxxxxxx>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Signed-off-by: John Harrison <John.C.Harrison@xxxxxxxxx>
Reviewed-by: Matthew Brost <matthew.brost@xxxxxxxxx>
Acked-by: Jon Bloomfield <jon.bloomfield@xxxxxxxxx>
Signed-off-by: Jordan Justen <jordan.l.justen@xxxxxxxxx>
---
+ ret = intel_guc_hwconfig_init(&guc->hwconfig);
+ if (ret)
+ drm_notice(&i915->drm, "Failed to retrieve hwconfig table: %pe\n",
Why only drm_notice? As you are keen to point out, the UMDs won't work
if the table is not available. All the failure paths in your own
verification function are 'drm_err'. So why is it only a 'notice' if
there is no table at all?
This was requested by Michal in my v3 posting:
https://patchwork.freedesktop.org/patch/472936/?series=99787&rev=3
I don't think that it should be a failure for i915 if it is unable to
read the table, or if the table read is invalid. I think it should be up
to the UMD to react to the missing hwconfig however they think is
appropriate, but I would like the i915 to guarantee & document the
format returned to userspace to whatever extent is feasible.
As you point out there is a discrepancy, and I think I should be
consistent with whatever is used here in my "drm/i915/guc: Verify
hwconfig blob matches supported format" patch.
I guess I'd tend to agree with Michal that "maybe drm_notice since we
continue probe", but I would go along with either if you two want to
discuss further.
having consistent message level is a clear benefit but on other hand
these other 'errors' may indicate more serious problems related to use
of wrong/incompatible firmware that returns corrupted HWconfig (or we
use wrong actions), while since we are not using this HWconfig in the
driver we don't care that much that we failed to load HWconfig and
'notice' is enough.
but I'm fine with all messages being drm_err (as we will not have to
change that once again after HWconfig will be mandatory for the driver
as well)
I would be against drm_err.
#define KERN_EMERG KERN_SOH "0" /* system is unusable */
#define KERN_ALERT KERN_SOH "1" /* action must be taken immediately */
#define KERN_CRIT KERN_SOH "2" /* critical conditions */
#define KERN_ERR KERN_SOH "3" /* error conditions */
#define KERN_WARNING KERN_SOH "4" /* warning conditions */
#define KERN_NOTICE KERN_SOH "5" /* normal but significant condition */
#define KERN_INFO KERN_SOH "6" /* informational */
#define KERN_DEBUG KERN_SOH "7" /* debug-level messages */
From the point of view of the kernel driver, this is not an error to its operation. It can at most be a warning, but notice is also fine by me. One could argue when reading "normal but significant condition" that it is not normal, when it is in fact unexpected, so if people prefer warning that is also okay by me. I still lean towards notice becuase of the hands-off nature i915 has with the pass-through of this blob.
Note that this function is called as part of the reset path. The reset
path is not allowed to allocate memory. The table is stored in a
dynamically allocated object. Hence the IGT test failure. The table
query has to be done elsewhere at driver init time only.
Thanks for clearing this up. I did notice on dg2 that gpu resets were
causing a re-read of the hwconfig from GuC, but it definitely was not
clear to me that there would be a connection to the IGT failure that you
pointed out.
+ ERR_PTR(ret));
+
ret = guc_enable_communication(guc);
if (ret)
goto err_log_capture;
@@ -562,6 +567,8 @@ static void __uc_fini_hw(struct intel_uc *uc)
if (intel_uc_uses_guc_submission(uc))
intel_guc_submission_disable(guc);
+ intel_guc_hwconfig_fini(&guc->hwconfig);
+
__uc_sanitize(uc);
}
diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c
index 76e590fcb903..1d31e35a5154 100644
--- a/drivers/gpu/drm/i915/i915_pci.c
+++ b/drivers/gpu/drm/i915/i915_pci.c
@@ -990,6 +990,7 @@ static const struct intel_device_info adl_p_info = {
BIT(RCS0) | BIT(BCS0) | BIT(VECS0) | BIT(VCS0) | BIT(VCS2),
.ppgtt_size = 48,
.dma_mask_size = 39,
+ .has_guc_hwconfig = 1,
Who requested this change? It was previously done this way but the
instruction was that i915_pci.c is for hardware features only but that
this, as you seem extremely keen about pointing out at every
opportunity, is a software feature.
This was requested by Michal as well. I definitely agree it is a
software feature, but I was not aware that "i915_pci.c is for hardware
features only".
Michal, do you agree with this and returning to the previous method for
enabling the feature?
now I'm little confused as some arch direction was to treat FW as
extension of the HW so for me it was natural to have 'has_guc_hwconfig'
flag in device_info
if still for some reason it is undesired to mix HW and FW/SW flags
inside single group of flags then maybe we should just add separate
group of immutable flags where has_guc_hwconfig could be defined.
let our maintainers decide
Bah.. :)
And what was the previous method?
[comes back later]
Okay it was:
+static bool has_table(struct drm_i915_private *i915)
+{
+ if (IS_ALDERLAKE_P(i915))
+ return true;
Which sucks a bit if we want to argue it does not belong in device info.
Why can't we ask the GuC if the blob exists? In fact what would happen if one would call __guc_action_get_hwconfig on any GuC platform?
Regards,
Tvrtko
