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Message-ID: <a3edcd53-bcbe-7408-100c-3db52c897a18@linux.intel.com>
Date:   Tue, 18 Apr 2023 09:19:49 +0100
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Subject: Re: [RFC 1/3] drm/doc: Relax fdinfo string constraints
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To:     Rob Clark <robdclark@gmail.com>, dri-devel@lists.freedesktop.org
Cc:     Rob Clark <robdclark@chromium.org>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Jonathan Corbet <corbet@lwn.net>,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
References: <20230417201215.448099-1-robdclark@gmail.com>
 <20230417201215.448099-2-robdclark@gmail.com>
From:   Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Organization: Intel Corporation UK Plc
In-Reply-To: <20230417201215.448099-2-robdclark@gmail.com>
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Precedence: bulk


On 17/04/2023 21:12, Rob Clark wrote:
> From: Rob Clark <robdclark@chromium.org>
> 
> The restriction about no whitespace, etc, really only applies to the
> usage of strings in keys.  Values can contain anything (other than
> newline).
> 
> Signed-off-by: Rob Clark <robdclark@chromium.org>
> ---
>   Documentation/gpu/drm-usage-stats.rst | 29 ++++++++++++++-------------
>   1 file changed, 15 insertions(+), 14 deletions(-)
> 
> diff --git a/Documentation/gpu/drm-usage-stats.rst b/Documentation/gpu/drm-usage-stats.rst
> index 258bdcc8fb86..8e00d53231e0 100644
> --- a/Documentation/gpu/drm-usage-stats.rst
> +++ b/Documentation/gpu/drm-usage-stats.rst
> @@ -24,7 +24,7 @@ File format specification
>   - All keys shall be prefixed with `drm-`.
>   - Whitespace between the delimiter and first non-whitespace character shall be
>     ignored when parsing.
> -- Neither keys or values are allowed to contain whitespace characters.
> +- Keys are not allowed to contain whitespace characters.
>   - Numerical key value pairs can end with optional unit string.
>   - Data type of the value is fixed as defined in the specification.
>   
> @@ -39,12 +39,13 @@ Data types
>   ----------
>   
>   - <uint> - Unsigned integer without defining the maximum value.
> -- <str> - String excluding any above defined reserved characters or whitespace.
> +- <keystr> - String excluding any above defined reserved characters or whitespace.
> +- <valstr> - String.

Makes sense I think. At least I can't remember that I had special reason 
to word it as strict as it was. Lets give it some time to marinade so 
for later:

Acked-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Regards,

Tvrtko

>   
>   Mandatory fully standardised keys
>   ---------------------------------
>   
> -- drm-driver: <str>
> +- drm-driver: <valstr>
>   
>   String shall contain the name this driver registered as via the respective
>   `struct drm_driver` data structure.
> @@ -69,10 +70,10 @@ scope of each device, in which case `drm-pdev` shall be present as well.
>   Userspace should make sure to not double account any usage statistics by using
>   the above described criteria in order to associate data to individual clients.
>   
> -- drm-engine-<str>: <uint> ns
> +- drm-engine-<keystr>: <uint> ns
>   
>   GPUs usually contain multiple execution engines. Each shall be given a stable
> -and unique name (str), with possible values documented in the driver specific
> +and unique name (keystr), with possible values documented in the driver specific
>   documentation.
>   
>   Value shall be in specified time units which the respective GPU engine spent
> @@ -84,16 +85,16 @@ larger value within a reasonable period. Upon observing a value lower than what
>   was previously read, userspace is expected to stay with that larger previous
>   value until a monotonic update is seen.
>   
> -- drm-engine-capacity-<str>: <uint>
> +- drm-engine-capacity-<keystr>: <uint>
>   
>   Engine identifier string must be the same as the one specified in the
> -drm-engine-<str> tag and shall contain a greater than zero number in case the
> +drm-engine-<keystr> tag and shall contain a greater than zero number in case the
>   exported engine corresponds to a group of identical hardware engines.
>   
>   In the absence of this tag parser shall assume capacity of one. Zero capacity
>   is not allowed.
>   
> -- drm-memory-<str>: <uint> [KiB|MiB]
> +- drm-memory-<keystr>: <uint> [KiB|MiB]
>   
>   Each possible memory type which can be used to store buffer objects by the
>   GPU in question shall be given a stable and unique name to be returned as the
> @@ -126,10 +127,10 @@ The total size of buffers that are purgeable.
>   
>   The total size of buffers that are active on one or more rings.
>   
> -- drm-cycles-<str>: <uint>
> +- drm-cycles-<keystr>: <uint>
>   
>   Engine identifier string must be the same as the one specified in the
> -drm-engine-<str> tag and shall contain the number of busy cycles for the given
> +drm-engine-<keystr> tag and shall contain the number of busy cycles for the given
>   engine.
>   
>   Values are not required to be constantly monotonic if it makes the driver
> @@ -138,12 +139,12 @@ larger value within a reasonable period. Upon observing a value lower than what
>   was previously read, userspace is expected to stay with that larger previous
>   value until a monotonic update is seen.
>   
> -- drm-maxfreq-<str>: <uint> [Hz|MHz|KHz]
> +- drm-maxfreq-<keystr>: <uint> [Hz|MHz|KHz]
>   
>   Engine identifier string must be the same as the one specified in the
> -drm-engine-<str> tag and shall contain the maximum frequency for the given
> -engine.  Taken together with drm-cycles-<str>, this can be used to calculate
> -percentage utilization of the engine, whereas drm-engine-<str> only reflects
> +drm-engine-<keystr> tag and shall contain the maximum frequency for the given
> +engine.  Taken together with drm-cycles-<keystr>, this can be used to calculate
> +percentage utilization of the engine, whereas drm-engine-<keystr> only reflects
>   time active without considering what frequency the engine is operating as a
>   percentage of it's maximum frequency.
>