<div dir="ltr"> <div class="gmail_extra"> <div class="gmail_quote">On Mon, Jul 20, 2015 at 1:49 AM, Thierry Reding <<a href="mailto:thierry.reding@gmail.com" target="_blank">thierry.reding@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">From: Thierry Reding <<a href="mailto:treding@nvidia.com">treding@nvidia.com</a>> The DPAUX read/write FIFO registers aren't sequential in the register space, causing transfers larger than 4 bytes to cause accesses to non- existing FIFO registers. Fixes: 6b6b604215c6 ("drm/tegra: Add eDP support") Signed-off-by: Thierry Reding <<a href="mailto:treding@nvidia.com">treding@nvidia.com</a>> --- drivers/gpu/drm/tegra/dpaux.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) diff --git a/drivers/gpu/drm/tegra/dpaux.c b/drivers/gpu/drm/tegra/dpaux.c index d6b55e3e3716..a43a836e6f88 100644 --- a/drivers/gpu/drm/tegra/dpaux.c +++ b/drivers/gpu/drm/tegra/dpaux.c @@ -72,34 +72,32 @@ static inline void tegra_dpaux_writel(struct tegra_dpaux *dpaux, static void tegra_dpaux_write_fifo(struct tegra_dpaux *dpaux, const u8 *buffer, size_t size) { - unsigned long offset = DPAUX_DP_AUXDATA_WRITE(0); size_t i, j; - for (i = 0; i < size; i += 4) { - size_t num = min_t(size_t, size - i, 4); + for (i = 0; i < DIV_ROUND_UP(size, 4); i++) { + size_t num = min_t(size_t, size - i * 4, 4); unsigned long value = 0; for (j = 0; j < num; j++) - value |= buffer[i + j] << (j * 8); + value |= buffer[i * 4 + j] << (j * 8); - tegra_dpaux_writel(dpaux, value, offset++); + tegra_dpaux_writel(dpaux, value, DPAUX_DP_AUXDATA_WRITE(i)); } } static void tegra_dpaux_read_fifo(struct tegra_dpaux *dpaux, u8 *buffer, size_t size) { - unsigned long offset = DPAUX_DP_AUXDATA_READ(0); size_t i, j; - for (i = 0; i < size; i += 4) { - size_t num = min_t(size_t, size - i, 4); + for (i = 0; i < DIV_ROUND_UP(size, 4); i++) { + size_t num = min_t(size_t, size - i * 4, 4); unsigned long value; - value = tegra_dpaux_readl(dpaux, offset++); + value = tegra_dpaux_readl(dpaux, DPAUX_DP_AUXDATA_READ(i)); for (j = 0; j < num; j++) - buffer[i + j] = value >> (j * 8); + buffer[i * 4 + j] = value >> (j * 8); } } -- 2.4.5 </blockquote></div> </div><div class="gmail_extra"> </div><div class="gmail_extra">This fixes the issue that I reported earlier, so feel free to add my</div><div class="gmail_extra"> </div><div class="gmail_extra">Tested-by: Steev Klimaszewski <<a href="mailto:steev@gentoo.org">steev@gentoo.org</a>></div></div>