| 2023-09-13 03:34:15 |
AceLan Kao |
bug |
|
|
added bug |
| 2023-09-13 03:34:25 |
AceLan Kao |
bug task added |
|
linux-oem-6.5 (Ubuntu) |
|
| 2023-09-13 03:34:35 |
AceLan Kao |
nominated for series |
|
Ubuntu Jammy |
|
| 2023-09-13 03:34:35 |
AceLan Kao |
bug task added |
|
linux (Ubuntu Jammy) |
|
| 2023-09-13 03:34:35 |
AceLan Kao |
bug task added |
|
linux-oem-6.5 (Ubuntu Jammy) |
|
| 2023-09-13 03:34:35 |
AceLan Kao |
nominated for series |
|
Ubuntu Mantic |
|
| 2023-09-13 03:34:35 |
AceLan Kao |
bug task added |
|
linux (Ubuntu Mantic) |
|
| 2023-09-13 03:34:35 |
AceLan Kao |
bug task added |
|
linux-oem-6.5 (Ubuntu Mantic) |
|
| 2023-09-13 03:34:43 |
AceLan Kao |
linux (Ubuntu Jammy): status |
New |
Invalid |
|
| 2023-09-13 03:34:46 |
AceLan Kao |
linux-oem-6.5 (Ubuntu Mantic): status |
New |
Invalid |
|
| 2023-09-13 03:34:50 |
AceLan Kao |
linux (Ubuntu Mantic): assignee |
|
AceLan Kao (acelankao) |
|
| 2023-09-13 03:34:53 |
AceLan Kao |
linux-oem-6.5 (Ubuntu Jammy): assignee |
|
AceLan Kao (acelankao) |
|
| 2023-09-13 03:34:57 |
AceLan Kao |
linux (Ubuntu Mantic): status |
New |
In Progress |
|
| 2023-09-13 03:35:00 |
AceLan Kao |
linux-oem-6.5 (Ubuntu Jammy): status |
New |
In Progress |
|
| 2023-09-13 03:54:48 |
AceLan Kao |
bug |
|
|
added subscriber Canonical Hardware Enablement |
| 2023-09-13 03:54:53 |
AceLan Kao |
tags |
|
oem-priority originate-from-2033577 somerville |
|
| 2023-09-14 07:52:19 |
AceLan Kao |
description |
[Impact]
Boots up the system and sometimes we can see below messages and that leads to backlight driver doesn't get loaded.
[ 86.424880] dell_uart_backlight:dell_uart_get_display_mode:tx: 6a 10 85
[ 86.603936] [7439] dell_uart_backlight:dell_uart_get_display_mode:rx: NULL
[ 87.596047] dell_uart_backlight:dell_uart_get_display_mode:tx: 6a 10 85
[ 87.775209] [7439] dell_uart_backlight:dell_uart_get_display_mode:rx: NULL
[Fix]
After applying this patch, it appears that the read() command sometimes fails to receive a response, even when increasing the retry times. This could be due to our use of a spin lock to lock the UART port in the read() function, preventing us from calling read() immediately after a write() function.
fbf84fb368923 ("UBUNTU: SAUCE: platform/x86: dell-uart-backlight: replace chars_in_buffer() with flush_chars()")
To fix this we only need a small delay after the write() function to make it has time to clear its buffer.
[Test case]
1. Add dell_uart_backlight.dyndbg="+pt" to the kernel cmdline
2. Boots up the system and check dmesg
3. Make sure there is no dell_uart_backlight rx NULL message in dmesg
4. Try to unload/reload dell_uart_backlight couple times and check dmesg again
[Where problems could occur]
sleep for 1ms is pretty short that it's not possible to lead to messages loss. |
[Impact]
Boots up the system and sometimes we can see below messages and that leads to backlight driver doesn't get loaded.
[ 86.424880] dell_uart_backlight:dell_uart_get_display_mode:tx: 6a 10 85
[ 86.603936] [7439] dell_uart_backlight:dell_uart_get_display_mode:rx: NULL
[ 87.596047] dell_uart_backlight:dell_uart_get_display_mode:tx: 6a 10 85
[ 87.775209] [7439] dell_uart_backlight:dell_uart_get_display_mode:rx: NULL
[Fix]
After applying the patch below, it seems that the read() command may fail to receive a response, even when increasing the retry times. It never gets a response when it fails.
fbf84fb368923 ("UBUNTU: SAUCE: platform/x86: dell-uart-backlight: replace chars_in_buffer() with flush_chars()")
To fix this, try adding a small delay after the write() function as a workaround.
[Test case]
1. Add dell_uart_backlight.dyndbg="+pt" to the kernel cmdline
2. Boots up the system and check dmesg
3. Make sure there is no dell_uart_backlight rx NULL message in dmesg
4. Try to unload/reload dell_uart_backlight couple times and check dmesg again
[Where problems could occur]
sleep for 1ms is pretty short that it's not possible to lead to messages loss. |
|
| 2023-09-16 17:46:37 |
Ubuntu Kernel Bot |
tags |
oem-priority originate-from-2033577 somerville |
kernel-spammed-jammy-linux-oem-6.5-v2 oem-priority originate-from-2033577 somerville verification-needed-jammy-linux-oem-6.5 |
|
| 2023-09-19 16:04:20 |
Timo Aaltonen |
linux-oem-6.5 (Ubuntu Jammy): status |
In Progress |
Fix Committed |
|
| 2023-09-25 13:42:23 |
AceLan Kao |
tags |
kernel-spammed-jammy-linux-oem-6.5-v2 oem-priority originate-from-2033577 somerville verification-needed-jammy-linux-oem-6.5 |
kernel-spammed-jammy-linux-oem-6.5-v2 oem-priority originate-from-2033577 somerville verification-done-jammy-linux-oem-6.5 |
|
| 2023-10-03 10:26:53 |
Launchpad Janitor |
linux-oem-6.5 (Ubuntu Jammy): status |
Fix Committed |
Fix Released |
|
