| Message ID | 4umro86wvv84.MjDfYvt4P5uZryt8boBK8Q2@1EHFQ.trk.elasticemail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [RFC] rtw88: Fix startup problems for SDIO wifi plus UART Bluetooth | expand |
On 4/14/24 7:45 PM, Ping-Ke Shih wrote: > Larry Finger <larry.finger@gmail.com> wrote: >> >> I originally wondered if there was a power problem when both were simultaneously >> started, but I see that is not the case. To reiterate, the BT must start first >> and complete UART initialization before the wifi starts initializing. It seems >> to me that a suitable msleep() at the start of the SDIO probe routine seems to >> be a viable workaround even though it is not aesthetically pleasing. A sleep of >> 150 ms is too short, but 500 seems to work reliably. > > Suggest to apply this workaround but only if UART-BT + SDIO-WiFi, because SDIO > experts didn't remember they have met this problem. They need real hardware to > measure signals to know what it is wrong, but unfortunately they don't have > bandwidth to process this because of limitation of human resources. Sorry > for that. The OP at GitHub reported today that there was a DTB error for that chip [1]. I am going to drop the patch for the stable kernel, but I will still apply it to my rtw88 repo at GitHub.com. That way, users with older kernels will get the benefit of the msleep() even though their DTB may not be fixed. Thanks to you and the SDIO team for your efforts toward a problem that turned out to be in the kernel. Sorry for some noise. Larry [1] https://github.com/ROCKNIX/distribution/pull/63/files#diff-e2de6222b1794f89311bdc1597c1597c76f34503c575ea3f7e7ec9c5376218d6
diff --git a/drivers/net/wireless/realtek/rtw88/sdio.c b/drivers/net/wireless/realtek/rtw88/sdio.c index 0cae5746f540..eec0ad85be72 100644 --- a/drivers/net/wireless/realtek/rtw88/sdio.c +++ b/drivers/net/wireless/realtek/rtw88/sdio.c @@ -1325,6 +1325,34 @@ int rtw_sdio_probe(struct sdio_func *sdio_func, rtwdev->hci.ops = &rtw_sdio_ops; rtwdev->hci.type = RTW_HCI_TYPE_SDIO; + /* Insert a delay of 500 ms. Without the delay, the wifi part + * and the UART that controls Bluetooth interfere with one + * another resulting in the following being logged: + * + * Start of SDIO probe function. + * Bluetooth: HCI UART driver ver 2.3 + * Bluetooth: HCI UART protocol Three-wire (H5) registered + * of_dma_request_slave_channel: dma-names property of node '/serial@fe650000' + * missing or empty + * dw-apb-uart fe650000.serial: failed to request DMA +` * rtw_8821cs mmc3:0001:1: Firmware version 24.8.0, H2C version 12 + * rtw_8821cs mmc3:0001:1: sdio read32 failed (0x11080): -110 + * + * If the UART is finished initializing before the SDIO probe + * function startw, the following is logged: + * + * Bluetooth: HCI UART protocol Three-wire (H5) registered + * of_dma_request_slave_channel: dma-names property of node '/serial@fe650000' + * missing or empty + * dw-apb-uart fe650000.serial: failed to request DMA + * Start of SDIO probe function. + * rtw_8821cs mmc3:0001:1: Firmware version 24.8.0, H2C version 12 + * Bluetooth: hci0: RTL: examining hci_ver=08 hci_rev=000c lmp_ver=08 lmp_subver=8821 + * SDIO wifi works correctly. + * + * No adverse effects are observed from the delay. + */ + mdelay(500); ret = rtw_core_init(rtwdev); if (ret) goto err_release_hw;
As discussed in the links below, the SDIO part of RTW8821CS fails to start correctly if such startup happens while the UART portion of the chip is initializing. The logged results with such failure is [ 10.230516] rtw_8821cs mmc3:0001:1: Start of rtw_sdio_probe [ 10.306569] Bluetooth: HCI UART driver ver 2.3 [ 10.306717] Bluetooth: HCI UART protocol Three-wire (H5) registered [ 10.307167] of_dma_request_slave_channel: dma-names property of node '/serial@fe650000' missing or empty [ 10.307199] dw-apb-uart fe650000.serial: failed to request DMA [ 10.543474] rtw_8821cs mmc3:0001:1: Firmware version 24.8.0, H2C version 12 [ 10.730744] rtw_8821cs mmc3:0001:1: sdio read32 failed (0x11080): -110 [ 10.730923] rtw_8821cs mmc3:0001:1: sdio write32 failed (0x11080): -110 Due to the above errors, wifi fails to work. For those instances when wifi works, the following is logged: [ 10.452861] Bluetooth: HCI UART protocol Three-wire (H5) registered [ 10.453580] of_dma_request_slave_channel: dma-names property of node '/serial@fe650000' missing or empty [ 10.453621] dw-apb-uart fe650000.serial: failed to request DMA [ 10.455741] rtw_8821cs mmc3:0001:1: Start of rtw_sdio_probe [ 10.639186] rtw_8821cs mmc3:0001:1: Firmware version 24.8.0, H2C version 12 In this case, SDIO wifi works correctly. The correct case is ensured by adding an mdelay(500) statement before the call to rtw_core_init(). No adverse effects are observed. Link: https://1EHFQ.trk.elasticemail.com/tracking/click?d=1UfsVowwwMAM6kBoyumkHP3o7pYa4kGXhuklYI-QPLuVUi2ohkUG8HssjZcN67C_2TySHAezxTUVFT_8wvKkE9xqzm8H8qwhbclOJ9HB0cExNK65eHoXK4LaCW3PT7iyvMI3d6qqwN6PHhYj2GEblxeP4xr4CJPwZE7lyMCRTuxZ0 Link: https://1EHFQ.trk.elasticemail.com/tracking/click?d=XUEf4t8W9xt0czASPOeeDt8BnPqLK_YeGMMwadyXNu17p5TeSDk6RmEZ25rBt0-C5d-GR5IlKqu5URoKaespUAOAffgoysVTLbvgzQoAO57Ix1ChR-fYsf2VGRa1vIR9iWmNK1bUBvdHTZb0StprYVFMTYNi3fpihu3YoQYbaiZsYjqFovexmfiXfyHM3S00rqaJrXQwoylF4bELv8WaAC-QQM6OuDzE6rb32eW83smj0 Fixes: 65371a3f14e7 ("wifi: rtw88: sdio: Add HCI implementation for SDIO based chipsets") Signed-off-by: Larry Finger <Larry.Finger@gmail.com> Cc: stable@vger.kernel.org # v6.4+ --- drivers/net/wireless/realtek/rtw88/sdio.c | 28 +++++++++++++++++++++++ 1 file changed, 28 insertions(+)