feat(gpu): show VRAM in use as a bar with a percentage

Sum drm-resident-vram0 from DRM fdinfo, the same per-client counters
gputop reads, counting each drm-client-id once since a client repeats
its totals on every fd it holds. One grep over /proc/*/fdinfo, about
10ms warm, sampled through new_gate every ~2s.

The 12 GiB total is hardcoded: xe exposes no VRAM capacity in sysfs.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 41 insertions, 0 deletions

diff --git a/lib/data.lua b/lib/data.lua
index 7ae96a7..d02d0f7 100644
--- a/lib/data.lua
+++ b/lib/data.lua
@@ -690,4 +690,45 @@ function M.nvtable_parse(text)
   return seen and out or nil
 end
 
+-- VRAM in use on an xe device, in bytes, from DRM fdinfo: the same source
+-- gputop reads. Input is `grep -H` output, one 'path:key:<tab>value' line per
+-- field, so fields are grouped by the fd file they came from.
+--
+-- One client (drm-client-id) is usually open on several fds, each repeating
+-- the client's full totals, so clients are counted once, not fds. Buffers
+-- shared between clients are still counted in each, as gputop does.
+local UNIT = { B = 1, KiB = 1024, MiB = 1024 ^ 2, GiB = 1024 ^ 3 }
+
+function M.drm_vram_parse(text)
+  if type(text) ~= 'string' then return nil end
+  local fds = {}
+  for path, key, val in text:gmatch('([^\n]-):(drm%-[%w%-]+):%s*([^\n]*)') do
+    local fd = fds[path] or {}
+    fds[path] = fd
+    fd[key] = val
+  end
+  local seen, total = {}, nil
+  for _, fd in pairs(fds) do
+    local id = fd['drm-client-id']
+    local n, unit = (fd['drm-resident-vram0'] or ''):match('^(%d+)%s*(%a*)')
+    if fd['drm-driver'] == 'xe' and id and n and not seen[id] then
+      seen[id] = true
+      total = (total or 0) + tonumber(n) * (UNIT[unit ~= '' and unit or 'B'] or 1)
+    end
+  end
+  return total
+end
+
+-- ponytail: a popen per call, ~10ms warm; callers gate it. Only fds of
+-- processes readable by conky's user are seen, so another user's GPU client
+-- (a system service) is not counted.
+function M.drm_vram()
+  local p = io.popen("grep -sH -e '^drm-driver' -e '^drm-client-id'"
+    .. " -e '^drm-resident-vram0' /proc/[0-9]*/fdinfo/* 2>/dev/null")
+  if not p then return nil end
+  local out = p:read('*a')
+  p:close()
+  return M.drm_vram_parse(out)
+end
+
 return M