diff options
| author | Paul Hsieh | 2018-11-22 11:43:45 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2019-02-12 19:47:12 +0100 |
| commit | 1baca23ade65af672080550aac5da653e53f413c (patch) | |
| tree | 342744928a1e1c3bd8435a44f4d2fffe4d4dc067 /drivers/gpu/drm/amd | |
| parent | net: hns3: fix incomplete uninitialization of IRQ in the hns3_nic_uninit_vect... (diff) | |
| download | kernel-qcow2-linux-1baca23ade65af672080550aac5da653e53f413c.tar.gz kernel-qcow2-linux-1baca23ade65af672080550aac5da653e53f413c.tar.xz kernel-qcow2-linux-1baca23ade65af672080550aac5da653e53f413c.zip | |
drm/amd/display: Add retry to read ddc_clock pin
[ Upstream commit bd4905a9583c760da31ded7256dca6f71483c3dc ]
[WHY]
On customer board, there is one pluse (1v , < 1ms) on
DDC_CLK pin when plug / unplug DP cable. Driver will read
it and config DP to HDMI/DVI dongle.
[HOW]
If there is a real dongle, DDC_CLK should be always pull high.
Try to read again to recovery this special case. Retry times = 3.
Need additional 3ms to detect DP passive dongle(3 failures)
Signed-off-by: Paul Hsieh <paul.hsieh@amd.com>
Reviewed-by: Eric Yang <eric.yang2@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/gpu/drm/amd')
| -rw-r--r-- | drivers/gpu/drm/amd/display/dc/core/dc_link.c | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link.c b/drivers/gpu/drm/amd/display/dc/core/dc_link.c index 7c89785fd731..23a7ef97afdd 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c @@ -324,7 +324,7 @@ bool dc_link_is_dp_sink_present(struct dc_link *link) { enum gpio_result gpio_result; uint32_t clock_pin = 0; - + uint8_t retry = 0; struct ddc *ddc; enum connector_id connector_id = @@ -353,11 +353,22 @@ bool dc_link_is_dp_sink_present(struct dc_link *link) return present; } - /* Read GPIO: DP sink is present if both clock and data pins are zero */ - /* [anaumov] in DAL2, there was no check for GPIO failure */ - - gpio_result = dal_gpio_get_value(ddc->pin_clock, &clock_pin); - ASSERT(gpio_result == GPIO_RESULT_OK); + /* + * Read GPIO: DP sink is present if both clock and data pins are zero + * + * [W/A] plug-unplug DP cable, sometimes customer board has + * one short pulse on clk_pin(1V, < 1ms). DP will be config to HDMI/DVI + * then monitor can't br light up. Add retry 3 times + * But in real passive dongle, it need additional 3ms to detect + */ + do { + gpio_result = dal_gpio_get_value(ddc->pin_clock, &clock_pin); + ASSERT(gpio_result == GPIO_RESULT_OK); + if (clock_pin) + udelay(1000); + else + break; + } while (retry++ < 3); present = (gpio_result == GPIO_RESULT_OK) && !clock_pin; |