On Wed, 2025-01-22 at 21:11 -0800, Lucas De Marchi wrote:
Commit 70fb86a85dc9 ("drm/xe: Revert some changes that break a mesa debug tool") partially reverted some changes to workaround breakage caused to mesa tools. However, in doing so it also broke fetching the GuC log via debugfs since xe_print_blob_ascii85() simply bails out.
The fix is to avoid the extra newlines: the devcoredump interface is line-oriented and adding random newlines in the middle breaks it. If a tool is able to parse it by looking at the data and checking for chars that are out of the ascii85 space, it can still do so. A format change that breaks the line-oriented output on devcoredump however needs better coordination with existing tools.
Cc: John Harrison John.C.Harrison@Intel.com Cc: Julia Filipchuk julia.filipchuk@intel.com Cc: José Roberto de Souza jose.souza@intel.com Cc: stable@vger.kernel.org Fixes: 70fb86a85dc9 ("drm/xe: Revert some changes that break a mesa debug tool") Fixes: ec1455ce7e35 ("drm/xe/devcoredump: Add ASCII85 dump helper function") Signed-off-by: Lucas De Marchi lucas.demarchi@intel.com
drivers/gpu/drm/xe/xe_devcoredump.c | 30 +++++++++-------------------- drivers/gpu/drm/xe/xe_devcoredump.h | 2 +- drivers/gpu/drm/xe/xe_guc_ct.c | 3 ++- drivers/gpu/drm/xe/xe_guc_log.c | 4 +++- 4 files changed, 15 insertions(+), 24 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_devcoredump.c b/drivers/gpu/drm/xe/xe_devcoredump.c index a7946a76777e7..d9b71bb690860 100644 --- a/drivers/gpu/drm/xe/xe_devcoredump.c +++ b/drivers/gpu/drm/xe/xe_devcoredump.c @@ -391,42 +391,30 @@ int xe_devcoredump_init(struct xe_device *xe) /**
- xe_print_blob_ascii85 - print a BLOB to some useful location in ASCII85
- The output is split to multiple lines because some print targets, e.g. dmesg
- cannot handle arbitrarily long lines. Note also that printing to dmesg in
- piece-meal fashion is not possible, each separate call to drm_puts() has a
- line-feed automatically added! Therefore, the entire output line must be
- constructed in a local buffer first, then printed in one atomic output call.
- The output is split to multiple print calls because some print targets, e.g.
- dmesg cannot handle arbitrarily long lines. These targets may add newline
- between calls.
- There is also a scheduler yield call to prevent the 'task has been stuck for
- 120s' kernel hang check feature from firing when printing to a slow target
- such as dmesg over a serial port.
- TODO: Add compression prior to the ASCII85 encoding to shrink huge buffers down.
*/
- @p: the printer object to output to
- @prefix: optional prefix to add to output string
- @blob: the Binary Large OBject to dump out
- @offset: offset in bytes to skip from the front of the BLOB, must be a multiple of sizeof(u32)
- @size: the size in bytes of the BLOB, must be a multiple of sizeof(u32)
-void xe_print_blob_ascii85(struct drm_printer *p, const char *prefix, +void xe_print_blob_ascii85(struct drm_printer *p, const char *prefix, char suffix,
just missing document the suffix.
With that this patch is:
Reviewed-by: José Roberto de Souza jose.souza@intel.com
const void *blob, size_t offset, size_t size){ const u32 *blob32 = (const u32 *)blob; char buff[ASCII85_BUFSZ], *line_buff; size_t line_pos = 0;
- /*
* Splitting blobs across multiple lines is not compatible with the mesa* debug decoder tool. Note that even dropping the explicit '\n' below* doesn't help because the GuC log is so big some underlying implementation* still splits the lines at 512K characters. So just bail completely for* the moment.*/- return;
#define DMESG_MAX_LINE_LEN 800 -#define MIN_SPACE (ASCII85_BUFSZ + 2) /* 85 + "\n\0" */
- /* Always leave space for the suffix char and the \0 */
+#define MIN_SPACE (ASCII85_BUFSZ + 2) /* 85 + "<suffix>\0" */ if (size & 3) drm_printf(p, "Size not word aligned: %zu", size); @@ -458,7 +446,6 @@ void xe_print_blob_ascii85(struct drm_printer *p, const char *prefix, line_pos += strlen(line_buff + line_pos); if ((line_pos + MIN_SPACE) >= DMESG_MAX_LINE_LEN) {
line_buff[line_pos++] = '\n'; line_buff[line_pos++] = 0;drm_puts(p, line_buff); @@ -470,10 +457,11 @@ void xe_print_blob_ascii85(struct drm_printer *p, const char *prefix, } }
- if (suffix)
line_buff[line_pos++] = suffix;- if (line_pos) {
line_buff[line_pos++] = '\n';- drm_puts(p, line_buff); }
diff --git a/drivers/gpu/drm/xe/xe_devcoredump.h b/drivers/gpu/drm/xe/xe_devcoredump.h index 6a17e6d601022..5391a80a4d1ba 100644 --- a/drivers/gpu/drm/xe/xe_devcoredump.h +++ b/drivers/gpu/drm/xe/xe_devcoredump.h @@ -29,7 +29,7 @@ static inline int xe_devcoredump_init(struct xe_device *xe) } #endif -void xe_print_blob_ascii85(struct drm_printer *p, const char *prefix, +void xe_print_blob_ascii85(struct drm_printer *p, const char *prefix, char suffix, const void *blob, size_t offset, size_t size); #endif diff --git a/drivers/gpu/drm/xe/xe_guc_ct.c b/drivers/gpu/drm/xe/xe_guc_ct.c index 8b65c5e959cc2..50c8076b51585 100644 --- a/drivers/gpu/drm/xe/xe_guc_ct.c +++ b/drivers/gpu/drm/xe/xe_guc_ct.c @@ -1724,7 +1724,8 @@ void xe_guc_ct_snapshot_print(struct xe_guc_ct_snapshot *snapshot, snapshot->g2h_outstanding); if (snapshot->ctb)
xe_print_blob_ascii85(p, "CTB data", snapshot->ctb, 0, snapshot->ctb_size);
xe_print_blob_ascii85(p, "CTB data", '\n',snapshot->ctb, 0, snapshot->ctb_size);diff --git a/drivers/gpu/drm/xe/xe_guc_log.c b/drivers/gpu/drm/xe/xe_guc_log.c index 80151ff6a71f8..44482ea919924 100644 --- a/drivers/gpu/drm/xe/xe_guc_log.c +++ b/drivers/gpu/drm/xe/xe_guc_log.c @@ -207,8 +207,10 @@ void xe_guc_log_snapshot_print(struct xe_guc_log_snapshot *snapshot, struct drm_ remain = snapshot->size; for (i = 0; i < snapshot->num_chunks; i++) { size_t size = min(GUC_LOG_CHUNK_SIZE, remain);
const char *prefix = i ? NULL : "Log data";char suffix = i == snapshot->num_chunks - 1 ? '\n' : 0;
xe_print_blob_ascii85(p, i ? NULL : "Log data", snapshot->copy[i], 0, size);
xe_print_blob_ascii85(p, prefix, suffix, snapshot->copy[i], 0, size);}