Re: [PATCH 3/3] vt: add DECRQM support to report mode states

[sashiko-bot@kernel.org]

> From: Nicolas Pitre <npitre@baylibre.com>
> 
> Applications currently have no way to find out whether the VT supports
> a given mode, nor what its current state is. DECRQM, "CSI Ps $ p" for
> ANSI modes and "CSI ? Ps $ p" for DEC private modes, is the standard
> query for this. But the '$' intermediate makes the parser ignore the
> whole sequence, leaving applications waiting for a reply that never
> comes.
> 
> This matters especially for mode 2027, whose specification relies on
> DECRQM for applications to detect support before enabling it.
> 
> Add an ESdollar parser state for "CSI parameters $", and answer a final
> 'p' with DECRPM, "CSI [?] Ps ; Pm $ y", where Pm is 1 (set), 2 (reset),
> 0 (not recognized) or 4 (permanently reset). All modes handled by
> csi_DEC_hl() and csi_hl() are reported, with 132-column mode reported
> as permanently reset since it isn't implemented. Other sequences using
> the '$' intermediate are still ignored.
> 
> Assisted-by: LLM
> Signed-off-by: Nicolas Pitre <npitre@baylibre.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/cover.1792443833.git.npitre@baylibre.com?part=3