diff mbox series

[1/1,SRU,OEM-B-OSP1,F,OEM-5.6,G] thunderbolt: Retry DROM read once if parsing fails

Message ID 20200915033220.165985-2-acelan.kao@canonical.com
State New
Headers show
Series Thunderbolt3 daisy chain sometimes doesn't work | expand

Commit Message

AceLan Kao Sept. 15, 2020, 3:32 a.m. UTC
From: Mika Westerberg <mika.westerberg@linux.intel.com>

BugLink: https://bugs.launchpad.net/bugs/1895606

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>
(cherry picked from commit f022ff7bf377ca94367be05de61277934d42ea74
linux-next)
Signed-off-by: AceLan Kao <acelan.kao@canonical.com>
---
 drivers/thunderbolt/eeprom.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

Comments

Kleber Souza Sept. 16, 2020, 9:09 a.m. UTC | #1
On 15.09.20 05:32, AceLan Kao wrote:
> From: Mika Westerberg <mika.westerberg@linux.intel.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1895606
> 
> 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>
> (cherry picked from commit f022ff7bf377ca94367be05de61277934d42ea74
> linux-next)
> Signed-off-by: AceLan Kao <acelan.kao@canonical.com>

Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

> ---
>  drivers/thunderbolt/eeprom.c | 20 ++++++++++++++++----
>  1 file changed, 16 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/thunderbolt/eeprom.c b/drivers/thunderbolt/eeprom.c
> index ee5196479854..fa491944de1a 100644
> --- a/drivers/thunderbolt/eeprom.c
> +++ b/drivers/thunderbolt/eeprom.c
> @@ -7,6 +7,7 @@
>   */
>  
>  #include <linux/crc32.h>
> +#include <linux/delay.h>
>  #include <linux/property.h>
>  #include <linux/slab.h>
>  #include "tb.h"
> @@ -386,8 +387,8 @@ static int tb_drom_parse_entries(struct tb_switch *sw)
>  		struct tb_drom_entry_header *entry = (void *) (sw->drom + pos);
>  		if (pos + 1 == drom_size || pos + entry->len > drom_size
>  				|| !entry->len) {
> -			tb_sw_warn(sw, "drom buffer overrun, aborting\n");
> -			return -EIO;
> +			tb_sw_warn(sw, "DROM buffer overrun\n");
> +			return -EILSEQ;
>  		}
>  
>  		switch (entry->type) {
> @@ -493,7 +494,8 @@ int tb_drom_read(struct tb_switch *sw)
>  	u16 size;
>  	u32 crc;
>  	struct tb_drom_header *header;
> -	int res;
> +	int res, retries = 1;
> +
>  	if (sw->drom)
>  		return 0;
>  
> @@ -581,7 +583,17 @@ int tb_drom_read(struct tb_switch *sw)
>  		tb_sw_warn(sw, "drom device_rom_revision %#x unknown\n",
>  			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:
>  	kfree(sw->drom);
>  	sw->drom = NULL;
>
diff mbox series

Patch

diff --git a/drivers/thunderbolt/eeprom.c b/drivers/thunderbolt/eeprom.c
index ee5196479854..fa491944de1a 100644
--- a/drivers/thunderbolt/eeprom.c
+++ b/drivers/thunderbolt/eeprom.c
@@ -7,6 +7,7 @@ 
  */
 
 #include <linux/crc32.h>
+#include <linux/delay.h>
 #include <linux/property.h>
 #include <linux/slab.h>
 #include "tb.h"
@@ -386,8 +387,8 @@  static int tb_drom_parse_entries(struct tb_switch *sw)
 		struct tb_drom_entry_header *entry = (void *) (sw->drom + pos);
 		if (pos + 1 == drom_size || pos + entry->len > drom_size
 				|| !entry->len) {
-			tb_sw_warn(sw, "drom buffer overrun, aborting\n");
-			return -EIO;
+			tb_sw_warn(sw, "DROM buffer overrun\n");
+			return -EILSEQ;
 		}
 
 		switch (entry->type) {
@@ -493,7 +494,8 @@  int tb_drom_read(struct tb_switch *sw)
 	u16 size;
 	u32 crc;
 	struct tb_drom_header *header;
-	int res;
+	int res, retries = 1;
+
 	if (sw->drom)
 		return 0;
 
@@ -581,7 +583,17 @@  int tb_drom_read(struct tb_switch *sw)
 		tb_sw_warn(sw, "drom device_rom_revision %#x unknown\n",
 			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:
 	kfree(sw->drom);
 	sw->drom = NULL;