On Mon, Apr 23, 2018 at 09:12:46AM -0700, Yunwei Zhang wrote:
> L3Bank could be fused off in hardware for debug purpose, and it
> is possible that subslice is enabled while its corresponding L3Bank pairs
> are disabled. In such case, if MCR packet control register(0xFDC) is
> programed to point to a disabled bank pair, a MMIO read into L3Bank range
> will return 0 instead of correct values.
>
> However, this is not going to be the case in any production silicon.
> Therefore, we only check at initialization and issue a warning should
> this really happen.
>
> References: HSDES#1405586840
>
> v2:
> - use fls instead of find_last_bit (Chris)
> - use is_power_of_2() instead of counting bit set (Chris)
> v3:
> - rebase on latest tip
> v5:
> - Added references (Mika)
> - Move local variable into scope where they are used (Ursulin)
> - use a new local variable to reduce long line of code (Ursulin)
> v6:
> - Some coding style and use more local variables for clearer
> logic (Ursulin)
> v7:
> - Rebased.
> v8:
> - Reviewed by Oscar.
> v9:
> - Fixed label location. (Oscar)
> v10:
> - Improved comments and replaced magical number. (Oscar)
>
> Cc: Oscar Mateo <oscar.mateo@xxxxxxxxx>
> Cc: Michel Thierry <michel.thierry@xxxxxxxxx>
> Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
> Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx>
> Signed-off-by: Yunwei Zhang <yunwei.zhang@xxxxxxxxx>
> Reviewed-by: Oscar Mateo <oscar.mateo@xxxxxxxxx>
I confess that I got lost on this thread, so please
accept my apologies in advance if I'm missing something here.
But I don't know anymore:
- if this series has 2 or 3 patches.
- which of the patches rv-b by Oscar are still valid
- if they are passing cleaning on CI.
So, my suggestion is to start a new series from scratch.
(resend all without any in-reply-to)
But please double check with Oscar if his rv-b should stay
on the new series.
Thanks,
Rodrigo.
> ---
> drivers/gpu/drm/i915/i915_reg.h | 4 ++++
> drivers/gpu/drm/i915/intel_device_info.c | 34 ++++++++++++++++++++++++++++++++
> 2 files changed, 38 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index fb10602..6c9c01b 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -2709,6 +2709,10 @@ enum i915_power_well_id {
> #define GEN10_F2_SS_DIS_SHIFT 18
> #define GEN10_F2_SS_DIS_MASK (0xf << GEN10_F2_SS_DIS_SHIFT)
>
> +#define GEN10_MIRROR_FUSE3 _MMIO(0x9118)
> +#define GEN10_L3BANK_PAIR_COUNT 4
> +#define GEN10_L3BANK_MASK 0x0F
> +
> #define GEN8_EU_DISABLE0 _MMIO(0x9134)
> #define GEN8_EU_DIS0_S0_MASK 0xffffff
> #define GEN8_EU_DIS0_S1_SHIFT 24
> diff --git a/drivers/gpu/drm/i915/intel_device_info.c b/drivers/gpu/drm/i915/intel_device_info.c
> index d917c9b..44ca90a 100644
> --- a/drivers/gpu/drm/i915/intel_device_info.c
> +++ b/drivers/gpu/drm/i915/intel_device_info.c
> @@ -729,6 +729,40 @@ static void sanitize_mcr(struct intel_device_info *info)
> u32 slice = fls(info->sseu.slice_mask);
> u32 subslice = fls(info->sseu.subslice_mask[slice]);
>
> + /*
> + * WaProgramMgsrForL3BankSpecificMmioReads: cnl,icl
> + * L3Banks could be fused off in single slice scenario. If that is
> + * the case, we might need to program MCR select to a valid L3Bank
> + * by default, to make sure we correctly read certain registers
> + * later on (in the range 0xB100 - 0xB3FF).
> + * This might be incompatible with
> + * WaProgramMgsrForCorrectSliceSpecificMmioReads.
> + * Fortunately, this should not happen in production hardware, so
> + * we only assert that this is the case (instead of implementing
> + * something more complex that requires checking the range of every
> + * MMIO read).
> + */
> + if (INTEL_GEN(dev_priv) >= 10 &&
> + is_power_of_2(info->sseu.slice_mask)) {
> + /*
> + * read FUSE3 for enabled L3 Bank IDs, if L3 Bank matches
> + * enabled subslice, no need to redirect MCR packet
> + */
> + u32 fuse3 = I915_READ(GEN10_MIRROR_FUSE3);
> + u8 ss_mask = info->sseu.subslice_mask[slice];
> +
> + u8 enabled_mask = (ss_mask | ss_mask >>
> + GEN10_L3BANK_PAIR_COUNT) &
> + GEN10_L3BANK_MASK;
> + u8 disabled_mask = fuse3 & GEN10_L3BANK_MASK;
> +
> + /*
> + * Production silicon should have matched L3Bank and
> + * subslice enabled
> + */
> + WARN_ON((enabled_mask & disabled_mask) != enabled_mask);
> + }
> +
> if (INTEL_GEN(dev_priv) >= 11) {
> mcr_slice_subslice_mask = GEN11_MCR_SLICE_MASK |
> GEN11_MCR_SUBSLICE_MASK;
> --
> 2.7.4
>
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