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thunderbolt: Retry DROM read once if parsing fails 

Kai-Heng reported that sometimes DROM parsing of ASUS PA27AC Thunderbolt 3
monitor fails. This makes the driver to fail to add the device so only
DisplayPort tunneling is functional.

It is not clear what exactly happens but waiting for 100 ms and retrying
the read seems to work this around so we do that here.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=206493
Reported-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
This commit is contained in:
Mika Westerberg 2020-09-07 12:20:36 +03:00
parent 813050e0a9
commit f022ff7bf3
1 changed files with 16 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
drivers/thunderbolt/eeprom.c
View File

@ -7,6 +7,7 @@
*/ */
#include <linux/crc32.h> #include <linux/crc32.h>
#include <linux/delay.h>
#include <linux/property.h> #include <linux/property.h>
#include <linux/slab.h> #include <linux/slab.h>
#include "tb.h" #include "tb.h"
@ -389,8 +390,8 @@ static int tb_drom_parse_entries(struct tb_switch *sw)
struct tb_drom_entry_header *entry = (void *) (sw->drom + pos); struct tb_drom_entry_header *entry = (void *) (sw->drom + pos);
if (pos + 1 == drom_size || pos + entry->len > drom_size if (pos + 1 == drom_size || pos + entry->len > drom_size
|| !entry->len) { || !entry->len) {
tb_sw_warn(sw, "drom buffer overrun, aborting\n"); tb_sw_warn(sw, "DROM buffer overrun\n");
return -EIO; return -EILSEQ;
} }
switch (entry->type) { switch (entry->type) {
@ -526,7 +527,8 @@ int tb_drom_read(struct tb_switch *sw)
u16 size; u16 size;
u32 crc; u32 crc;
struct tb_drom_header *header; struct tb_drom_header *header;
int res; int res, retries = 1;
if (sw->drom) if (sw->drom)
return 0; return 0;
@ -612,7 +614,17 @@ parse:
tb_sw_warn(sw, "drom device_rom_revision %#x unknown\n", tb_sw_warn(sw, "drom device_rom_revision %#x unknown\n",
header->device_rom_revision); header->device_rom_revision);
return tb_drom_parse_entries(sw); res = tb_drom_parse_entries(sw);
/* If the DROM parsing fails, wait a moment and retry once */
if (res == -EILSEQ && retries--) {
tb_sw_warn(sw, "parsing DROM failed, retrying\n");
msleep(100);
res = tb_drom_read_n(sw, 0, sw->drom, size);
if (!res)
goto parse;
}
return res;
err: err:
kfree(sw->drom); kfree(sw->drom);
sw->drom = NULL; sw->drom = NULL;