[PATCH] drm: mediatek: mtk_dsi: Fix NO_EOT_PACKET settings/handling
Alexandre Mergnat
amergnat at baylibre.com
Fri Jun 23 11:29:43 UTC 2023
On 23/06/2023 11:47, AngeloGioacchino Del Regno wrote:
> Il 23/05/23 12:42, AngeloGioacchino Del Regno ha scritto:
>> Due to the initial confusion about MIPI_DSI_MODE_EOT_PACKET, properly
>> renamed to MIPI_DSI_MODE_NO_EOT_PACKET, reflecting its actual meaning,
>> both the DSI_TXRX_CON register setting for bit (HSTX_)DIS_EOT and the
>> later calculation for horizontal sync-active (HSA), back (HBP) and
>> front (HFP) porches got incorrect due to the logic being inverted.
>>
>> This means that a number of settings were wrong because....:
>> - DSI_TXRX_CON register setting: bit (HSTX_)DIS_EOT should be
>> set in order to disable the End of Transmission packet;
>> - Horizontal Sync and Back/Front porches: The delta used to
>> calculate all of HSA, HBP and HFP should account for the
>> additional EOT packet.
>>
>> Before this change...
>> - Bit (HSTX_)DIS_EOT was being set when EOT packet was enabled;
>> - For HSA/HBP/HFP delta... all three were wrong, as words were
>> added when EOT disabled, instead of when EOT packet enabled!
>>
>> Invert the logic around flag MIPI_DSI_MODE_NO_EOT_PACKET in the
>> MediaTek DSI driver to fix the aforementioned issues.
>>
>> Fixes: 8b2b99fd7931 ("drm/mediatek: dsi: Fine tune the line time
>> caused by EOTp")
>> Fixes: 2d52bfba09d1 ("drm/mediatek: add non-continuous clock mode and
>> EOT packet control")
>> Signed-off-by: AngeloGioacchino Del Regno
>> <angelogioacchino.delregno at collabora.com>
>
> Gentle ping for an important fix.
>
> Regards,
> Angelo
>
>> ---
>> drivers/gpu/drm/mediatek/mtk_dsi.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
>> b/drivers/gpu/drm/mediatek/mtk_dsi.c
>> index 7d5250351193..b0ab38e59db9 100644
>> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
>> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
>> @@ -407,7 +407,7 @@ static void mtk_dsi_rxtx_control(struct mtk_dsi *dsi)
>> if (dsi->mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS)
>> tmp_reg |= HSTX_CKLP_EN;
>> - if (!(dsi->mode_flags & MIPI_DSI_MODE_NO_EOT_PACKET))
>> + if (dsi->mode_flags & MIPI_DSI_MODE_NO_EOT_PACKET)
>> tmp_reg |= DIS_EOT;
>> writel(tmp_reg, dsi->regs + DSI_TXRX_CTRL);
>> @@ -484,7 +484,7 @@ static void mtk_dsi_config_vdo_timing(struct
>> mtk_dsi *dsi)
>> timing->da_hs_zero + timing->da_hs_exit + 3;
>> delta = dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST ? 18 : 12;
>> - delta += dsi->mode_flags & MIPI_DSI_MODE_NO_EOT_PACKET ? 2 : 0;
>> + delta += dsi->mode_flags & MIPI_DSI_MODE_NO_EOT_PACKET ? 0 : 2;
>> horizontal_frontporch_byte = vm->hfront_porch * dsi_tmp_buf_bpp;
>> horizontal_front_back_byte = horizontal_frontporch_byte +
>> horizontal_backporch_byte;
>
>
Sounds logic
Reviewed-by: Alexandre Mergnat <amergnat at baylibre.com>
--
Regards,
Alexandre
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