Created
July 10, 2012 13:26
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0001-apple-gmux-Restore-switch-registers-on-suspend-resum.patch
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| From a2f5c540b903143e5a0b025cd2f81a69ad809072 Mon Sep 17 00:00:00 2001 | |
| From: Arun Raghavan <arun.raghavan@collabora.co.uk> | |
| Date: Tue, 10 Jul 2012 08:55:58 +0530 | |
| Subject: [PATCH] apple-gmux: Restore switch registers on suspend/resume | |
| After suspend and resume, the values of these registers seem to change | |
| from what they were at suspend time, potentially preventing the actual | |
| output lines from being enabled post-resume. This saves relevant state | |
| at suspend and restores it when resumed. | |
| This is at least required on the MacBook Pro 8.2 when the Intel GPU is | |
| manually selected in GRUB config before the kernel is loaded. | |
| Signed-off-by: Arun Raghavan <arun.raghavan@collabora.co.uk> | |
| --- | |
| drivers/platform/x86/apple-gmux.c | 29 ++++++++++++++++++++++++++++- | |
| 1 files changed, 28 insertions(+), 1 deletions(-) | |
| diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c | |
| index 694a15a..5a5d005 100644 | |
| --- a/drivers/platform/x86/apple-gmux.c | |
| +++ b/drivers/platform/x86/apple-gmux.c | |
| @@ -26,6 +26,11 @@ struct apple_gmux_data { | |
| unsigned long iolen; | |
| struct backlight_device *bdev; | |
| + | |
| + bool was_suspended; | |
| + u8 save_switch_ddc; | |
| + u8 save_switch_disp; | |
| + u8 save_switch_ext; | |
| }; | |
| /* | |
| @@ -87,8 +92,30 @@ static int gmux_update_status(struct backlight_device *bd) | |
| struct apple_gmux_data *gmux_data = bl_get_data(bd); | |
| u32 brightness = bd->props.brightness; | |
| - if (bd->props.state & BL_CORE_SUSPENDED) | |
| + if (bd->props.state & BL_CORE_SUSPENDED) { | |
| + /* Save mux settings for output lines since they get reset on | |
| + * suspend */ | |
| + gmux_data->was_suspended = TRUE; | |
| + gmux_data->save_switch_ddc = gmux_read8(gmux_data, | |
| + GMUX_PORT_SWITCH_DDC); | |
| + gmux_data->save_switch_disp = gmux_read8(gmux_data, | |
| + GMUX_PORT_SWITCH_DISPLAY); | |
| + gmux_data->save_switch_ext = gmux_read8(gmux_data, | |
| + GMUX_PORT_SWITCH_EXTERNAL); | |
| + | |
| return 0; | |
| + } | |
| + | |
| + if (gmux_data->was_suspended) { | |
| + /* Restore pre-suspend values for output lines */ | |
| + gmux_data->was_suspended = FALSE; | |
| + gmux_write8(gmux_data, GMUX_PORT_SWITCH_DDC, | |
| + gmux_data->save_switch_ddc); | |
| + gmux_write8(gmux_data, GMUX_PORT_SWITCH_DISPLAY, | |
| + gmux_data->save_switch_disp); | |
| + gmux_write8(gmux_data, GMUX_PORT_SWITCH_EXTERNAL, | |
| + gmux_data->save_switch_ext); | |
| + } | |
| /* | |
| * Older gmux versions require writing out lower bytes first then | |
| -- | |
| 1.7.8.6 |
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