On Thu, Mar 23, 2023 at 03:59:01PM -0700, Umesh Nerlige Ramappa wrote:
> OAM does not work with media C6 enabled on some steppings of MTL.
I just stumbled across this while looking at something else, but
14017512683 isn't a valid workaround number; that's just a per-platform
identifier associated with Wa_18023884638. The actual Wa_18023884638
applies not only to MTL, but also to DG2 which it looks like we're not
handling below.
Matt
> Disable OAM if we detect that media C6 was enabled in bios.
>
> v2: (Ashutosh)
> - Remove drm_notice from the driver load path
> - Log a drm_err when opening an OAM stream on affected steppings
>
> v3:
> - Initialize the engine group even if mc6 is enabled (Ashutosh)
> - Checkpatch fix
>
> Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@xxxxxxxxx>
> Reviewed-by: Ashutosh Dixit <ashutosh.dixit@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_perf.c | 31 +++++++++++++++++++++++++++++++
> 1 file changed, 31 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
> index 18afa76653b7..c035dbb84c9b 100644
> --- a/drivers/gpu/drm/i915/i915_perf.c
> +++ b/drivers/gpu/drm/i915/i915_perf.c
> @@ -209,6 +209,7 @@
> #include "gt/intel_gt_regs.h"
> #include "gt/intel_lrc.h"
> #include "gt/intel_lrc_reg.h"
> +#include "gt/intel_rc6.h"
> #include "gt/intel_ring.h"
> #include "gt/uc/intel_guc_slpc.h"
>
> @@ -4223,6 +4224,19 @@ static int read_properties_unlocked(struct i915_perf *perf,
> return -EINVAL;
> }
>
> + /*
> + * Wa_14017512683: mtl[a0..c0): Use of OAM must be preceded with Media
> + * C6 disable in BIOS. Fail if Media C6 is enabled on steppings where OAM
> + * does not work as expected.
> + */
> + if (IS_MTL_MEDIA_STEP(props->engine->i915, STEP_A0, STEP_C0) &&
> + props->engine->oa_group->type == TYPE_OAM &&
> + intel_check_bios_c6_setup(&props->engine->gt->rc6)) {
> + drm_dbg(&perf->i915->drm,
> + "OAM requires media C6 to be disabled in BIOS\n");
> + return -EINVAL;
> + }
> +
> i = array_index_nospec(props->oa_format, I915_OA_FORMAT_MAX);
> f = &perf->oa_formats[i];
> if (!engine_supports_oa_format(props->engine, f->type)) {
> @@ -5316,6 +5330,23 @@ int i915_perf_ioctl_version(struct drm_i915_private *i915)
> *
> * 7: Add support for video decode and enhancement classes.
> */
> +
> + /*
> + * Wa_14017512683: mtl[a0..c0): Use of OAM must be preceded with Media
> + * C6 disable in BIOS. If Media C6 is enabled in BIOS, return version 6
> + * to indicate that OA media is not supported.
> + */
> + if (IS_MTL_MEDIA_STEP(i915, STEP_A0, STEP_C0)) {
> + struct intel_gt *gt;
> + int i;
> +
> + for_each_gt(gt, i915, i) {
> + if (gt->type == GT_MEDIA &&
> + intel_check_bios_c6_setup(>->rc6))
> + return 6;
> + }
> + }
> +
> return 7;
> }
>
> --
> 2.36.1
>
--
Matt Roper
Graphics Software Engineer
Linux GPU Platform Enablement
Intel Corporation
